More research since yesterday has revealed why I could not find the road in the period, as there is a gap in the digitised records from 1939 to 1956, which is the period I want? Also, Highgate West Hill is in Camden now, certainly, and has been since 1965, but before that it was in St. Pancras North, Highgate polling district (A), Ward No 1. I found it in the 1956 electors registers finally, by which time my quarry had moved! Drat.
Thanks for your time anyway, that's how we progress with the help of other people.
Keith, in South Shields.