Could this be it?
There is a play running in the West End called Bliss.There was a composer called Sir Arthur Bliss.I don't know enough to say if there is a connection,though.
I did look on the interent a few days ago but found nothing.
I tried to think of popular conductors who may have had a play named after them, and names like Leonard Berstein sprang to mind, but I could not find anything.