Hi
Think I might be able to help out here.

James & Barbara Walker with family are living at SCOTS HILL, Croxley Green on the 1901. Scots Hill is right on the edge of Croxley into Rickmansworth.
I'm not absolutely sure which marriages or births you are looking for so if I have it wrong, apologies.
James Walker married Barbara Emma Francis in Amersham Buckinghamshire June qtr 1885. Ref 3a 675.
Peter James Walker born Dec qtr 1894 Watford ref 3a 604.
Watford is the registration district for Croxley Green & Rickmansworth.
As you mention the fact about Peter J having something to do with films, I wonder if he worked at the old Denham Studios just outside of Rickmansworth.
Hope it's helped a little bit.
Maddie