Good for Moriarty and Lydia

The whole thing is well played, not too much on the side of unbelievable, has great actors.
And yet, the IMDB-grade is relatively low for a Rathbone-Bruce movie. What is missing? I dunno. To me, it looks like being shot with little love and dedication, though I can't put my finger onto any tangible item.
I always go for the young Hillary Brooke! She is an attractive lady, and my first choice for attractive--mysterious woman. So I see her as perfect Lydia here, and likewise in The Ministry of Fear in a similar capacity.