Imagine – it’s opening night of a long-awaited new musical on London’s West End. Can director Larry Goldblatt (David Bedella) succeed where Sir Laurence Olivier, Sir Peter Hall, and Peter Brook have failed? Will the book surpass those of Harold Pinter, Howard Brenton, or National Treasure Alan Bennett? Might the music eclipse that of Stephen Sondheim?

The audience gurgles with anticipation. We’re about to witness, in musical theatre style, the tempestuous relationship between a truly great artist and another artist (a woman), and the whole history of modernism – all in 70 minutes!

This is the premise of Mel Brimfield and Gwyneth Herbert’s joyful show about Henry Moore and Barbara Hepworth, staged at Wilton’s for three performances only, with a hastily-gathered top-notch cast, a punchy band, and PowerPoint. Described by the makers as ‘a fictitious lost musical reconstructed in fragments’, it neatly skewers gender politics, artistic status, and performing arts practice, in one sweep of its razor-sharp chisel.

The back story to the musical’s three decades of wrangling by theatrical luminaries is told via a spoof Arena TV programme. It sets the tone for the evening: clever, funny writing and inventive music, brought to life in performance and on film.

The Starling Arts Choir opens the show, rehearsing Truth to Materials. Their voices are stratified: sopranos are marble, altos are plaster, basses bronze, belting out that they are ‘together releasing the form’ – as much a comment on contemporary performance as it is a definition of modernist sculpture. This subtle intelligence is at play throughout.

There is the characterization of Henry as a DH Lawrence archetype, pictured hugging the ‘vital trunks’ of trees, while Barbara moons over dangling catkins and pink anemones. Andrew C Wadsworth is a glorious Henry, with just the right amount of swagger and Yorkshire vowels, singing a lusty paean to Adel Rock. As Barbara, Frances Ruffele’s solo show-stopping number defines the status of women in art through lines like ‘My shapes were bold, his were archetypal.’ She inhabits a world where stone replaces the glass in the ceiling. We feel for Barbara chipping away at her monumental blocks, quietly changing the face of British sculpture – from representation into abstraction – in the shadow of the Yorkshire titan and his money-making enterprises.

The personal relationship between sculptors is deftly traced. Henry’s star rises while Barbara cares for the triplets, his international reputation burgeoning while she has Hull.

It is a shame that the ambition, stated in the publicity, for ‘breathtaking set design’ didn’t manifest at these performances. I missed the visual elements that looked so alluring in pre-show clips. There are spoken interludes, featuring the rounded tones of Hugh Ross as The Critic, and moments of recorded interviews against archive film that would have benefitted from a richer palette, particularly given the grandeur of the space. The performances are all first rate; David Bedella (Jerry Springer’s Satan), reading from notes, injects real West-End glamour.

Hopefully the piece will be developed further and the slightly odd conjunctions and transitions eased out. I wonder too whether leaving us with the refrain of Springtime for Hitler and Germany (from The Producers) is the right decision? It does scan beautifully as Henry and Barbara, but given Gwyneth’s evident talent for a song and a tune, it would have been great to have left humming something of hers.

Mel Brimfield has been delving into the lives of artists for several years, creating wonderfully playful films and installations that pack a punch. It was lovely to hear Joanna Neary’s pitch-perfect narration to a film of Barbara Hepworth at work (from 2011). This final fragment of the evening overturned the whole premise of the musical, showing that Barbara too was driven and pompous; ‘Sometimes a low wattage bulb is just what one needs’ she drawls, referring to Henry’s mediocrity.

Springtime for Henry (and Barbara) has been lovingly developed by two highly accomplished and idiosyncratic talents, and I for one would be thrilled to see it take its natural place on Broadway.

Everyone here is trapped. Welsh ex-squaddie Zach (David Woods) has retreated to a cardboard box. His wife Carol (Jon Haynes) is trapped out of sight, perhaps in her own box, perhaps upside down, certainly in an unforgiving marriage. Band mate and fellow war veteran Ieuan (Jon Haynes again) is trapped outside by the door-chain and by the demands of his bowels. It doesn’t take long, in this off-kilter world, for the audience to recognize its own position: trapped in a similarly dark box to Zach’s, on hard seats, in a cold auditorium. And hold on, aren’t the actors also hiding from us, literally, behind scenery and inside cardboard?

So the form matches the subject – Zach can’t find a way to escape the cage of his trauma – would mind-altering drugs help?

The story unfolds in Ridiculusmus’s signature style. We have two main quarrelsome characters, in a bizarre situation, struggling to debate a serious issue, this time about the use of mind-altering drugs such as MDMA to treat post-traumatic stress disorder.

Give Me Your Love is the second play of the company’s trilogy exploring the relationship between therapeutic innovation and mental health service users. The first, The Eradication of Schizophrenia in Western Lapland, was more ambitious in terms of staging and company size, but they share a basis in scientific research partnered with playful theatrical treatment. There are overlaps too in the way drama builds, and how catharsis has to be almost forced from the sufferer.

For Zach, ‘getting the trauma out’ is really hard. He’s tried Prolonged Exposure and it didn’t help. Does he need a therapist, like Ieuan had? Would listening to the Prodigy help? He understands that he can’t stay in a box for much longer, and if CNN said MDMA can help, and if they’ve tried it in Cardiff, then hell yes he’ll swallow the pill. But Zach is slippery. We can’t be certain that he has taken the drug, he invents a traumatic scene to get things moving, he says that his trauma is that he did nothing in the war, just sat on his ‘fat arse’. It’s almost as if his trauma is a fear of modern life; of doing nothing, being bored, feeling trapped. The language is classic Ridiculusmus, conversational and distinctive, slyly mixing the everyday with the metaphysical. An exchange about a Swiss Army Knife versus Leatherman leads seamlessly into a discussion on suicide; Ieuan drops in the line ‘keep them entertained, Zach’ acknowledging our presence.

If this sounds a bit grim, the performances and the writing prove otherwise. It’s almost an installation piece, this room with an animated box and choreographed motifs; Ieuan’s hands arcing gracefully through the gap in the door, Jon’s sudden appearance as a shell-shocked war veteran in white pants under a strobe light (lighting by Richard Vabre); the blatantly unnecessary use of a pulley as a dramatic device. The set, by Jacob Williams, looks like a cross between a condemned cell and a student squat, with a nod to a dirty protest. Having your actors either off-stage or concealed doesn’t help with audibility though, and some dialogue was very muffled.

The lack of physical presence does reduce the pleasure a notch for those who particularly enjoy Woods’s edgy explosive persona and Haynes’s dead-pan, slightly wheedling one. But Zach and Ieuan are well drawn despite being mainly invisible. We feel Zach’s frustration and readiness to try anything to escape his mental prison. Ieuan seems a bit of a chancer, but he is a proper friend and eager to help – even to procuring illegal ecstasy of dodgy provenance. I love that he doesn’t realize that Zach is in a box until very near the end. Carol, the off-stage wife, is beautifully sketched, perhaps with an addiction to painkillers and problems of her own. The action is punctuated with a fantastic sound design and music by Marco Cher-Gibard that underpins Zach’s emotional journey. The final coda, playing out in darkness, is wonderfully haunting.

There is no definitive point of view on offer here; the play rather skitters over its subject despite the in-depth research embedded in it. But as with many Ridiculusmus shows, the work is intrinsically dramatic. From Tough Time, Nice Time (performed in a bath tub), Yes, Yes, Yes (performed as two psychiatric patients) through to Say Nothing (performed on a piece of fake grass), Ridiculusmus continually reinvent theatre and speak with a unique voice.

Give Me Your Love ends with a glimmer of hope. Zach has had some kind of epiphany, however temporary. There is birdsong, a planned trip to the beach with an umbrella, the promise of an all-you-can-eat-buffet. But there is a sense too of hopelessness. Larger MDMA trials will start soon in America, but the UK is slow to invest in this form of therapy. So for Zach, and the one in nine soldiers that, it is said, suffer from post-traumatic stress disorder, the psychedelic trip-cure is still a long way down the rainbow-coloured road.

Dreamthinkspeak has an international reputation for creating extraordinary immersive theatre installations and its latest production, Absent, is a welcome addition to its canon.

The experience begins before you enter the building. The transformation of the exterior of Shoreditch Town Hall into a hotel is so effective that I actually walked straight past it. Inspired by the life of the Duchess of Argyll, who lived in a luxury hotel until eventually evicted, the piece is a haunting exploration of loneliness, declining gentility and corporate greed.

The audience is free to wander a building in transition, filled with ghosts of the past and glimpses of the future.

Artistic Director Tristan Sharps has always been fascinated by architectural models and here they are a perfect fit for the subject. Absent is about a building changing from grand to functional and we are potential investors on a viewing.  The switches from macro to micro make sense. The Shoreditch Group’s profits are booming, room rates start at £60, the project will regenerate the area. It is grimly real. Just read the Evening Standard.

As in most of his work, Sharps plays here with scale and form, using film and false mirrors, inviting us through wardrobe doors into barren spaces, leaving clues of habitation. Here a bottle of Chantal perfume on a creaky shelf, its scent pervading the room, there a pile of Burmatex carpet tiles ready for laying. I felt like a forensic scientist investigating a missing person.

It is not a spoiler to say (as Sharps did on Radio 4) that there is a lack of physical presence in the piece. Had I known in advance, I would have spent more time observing the one live actress playing Margaret de Beaumont. Fortunately the filmed world is compelling and evocative, featuring a luminous performance by Marion Déprez.

Absent is a simpler piece to those of recent years but no less powerful. In The Beginning Was The End (2013), at Somerset House, inspired by Leonardo da Vinci, was playful and interactive, brightly lit and slightly scary. Before I Sleep, which I saw at the old Co-Op in Brighton, 2010, was a lavish and thrilling take on The Cherry Orchard with a cast of hundreds.  Whereas in those productions the building was a space in which to make the work, in Absent the building is the work. There are some familiar tropes – the bringing of ‘outside’ into this interior landscape, a child, a gentle sound-score, and the silent guides. If the scale is more of a novella than epic, it remains a beautifully executed experience.

On leaving, you can’t help but notice how pertinent the vision is, with gentrification all around. The former magistrates’ court and police station opposite is, guess what? A hotel.