Here’s an unassuming little festival treat: a straightforward, well-made ensemble play for adults (and by that, I don’t mean smutty, but simply grown-up).

If there’s a gimmick per se, it comes in the form of David Cassidy – now retro chic again after various celebrities have outed themselves as former fans. But Cassidy is merely a catalyst to return the group of now middle-aged friends to a more innocent time, the week in 1973 when he visited London for a concert at Wembley, and turned their 15-year-old existences upside down.

It becomes clear that the seeds of their present-day problems and disillusionments were planted all those years ago. And with the excellent six-strong company – Mark Carlisle, Frances Lima, Steve North and Kevin Pallister as well as co-writers Lucie Fitchett and Victoria Willing – playing both their real ages and their younger selves, with touching naivete, the point is even more effective. But there are also seeds of hope, and as the rushed ending demonstrates, it’s never too late to water those and watch them grow

To borrow a lyric from David, I think I love it – in fact, I’m sure I do. I look forward to an expanded version that will give these engaging and totally realistic characters more space to breathe.