The Scarlet Pimpernel
I remembered that I prepared a cast list for the first picture some years ago. At that time I made this note: The following are listed in the programme - Alan Humphreys, David Orton, Anthony Read. Three names in all for only one place that suggests that a couple of bit part characters had already left for home when the picture was taken; presumably at the Dress Rehearsal.
Tony, Robin or David might be able to identify the 4th from the left, front row and also confirm the names of the others.