Saw this on the Talking Pictures channel (UK - older films and TV shows from yesteryear). I've seen various versions of these stories over the decades, I wasn't aware of this one before.
Now I've seen one, I certainly won't be rushing to try a second.
Other reviewers have stated that the aim was light comedy, and the actors and direction were somewhat tongue-in-cheek, though solving various mysteries along the way.
I thought the whole thing was abysmal, hammy acting, not helped by the director emphasising 'clues' for even the blindest audience, and the attempted humour painful even by those early 50s standards.
Despite as one reviewer points out Dr Watson being an expert on train timetables, in one early line they calculate that getting from London to Sussex will take just over 4 hours. Well, in those days, you could get from London to Brighton in an hour, and with branch lines still open (10 years or so before the wretched Beeching cuts) that 4 hours would have been total twaddle.
Oh, and why were (apparently) the exteriors shot in France? Bizarre.
Two out of 10, and that's being kind.