Again, I am sure he and the girl he is holding in a reassuring hug are portraits of actors in role. In fact, I think I have identified the pipe-smoking figure to the left. The character is obviously Sherlock Holmes, and the actor is probably Tod Slaughter, famous for playing villainous villains in melodramas at the Elephant and Castle. Sweeney Todd, the Demon Barber of Fleet Street was created by him.
In the 1920s, however, he played heroes, one of which was the great detective.
Come to think of it, is the cloaked assassin in the same play with Holmes? Which of the stories features a shooting?
Back in the late 1960s when I started work, I knew a bloke called Michael Slaughter, who was always known as Tod. Neither he nor any of us knew why - it was just the nickname every Slaughter was given, like 'Chalky' for anyone called White or Miller. How quickly fame evaporates....