Ah, I have:
A
L
A/R
M
I/S
T
to fit in with ALAR and IMPLANTS
but I could be wrong as I still have about a third of the clues to solve.
The film is extremely well-known, well to me at least. It was one of a series made by the two stars in the 1930s and it was shown on BBC2 on Saturday afternoon a few weeks ago. Have you read post 26?The two stars are identified by their surnames.