In Biggles Takes a Hand, Westwinds, 11 Bishop's Way, Hampstead, was the residence of Dr Bruno Jacobs. Some time before the events in the book, Dr Jacobs, who used to run his dental practice at Westwinds, decided to retire and move to the countryside. The house remained on the market some three months become being sold to one Mrs Smith, who moved in and had stayed there for six months before the Roths called there looking for Jacobs.
Westwinds is a fictional location, as is Bishop's Way. London does have a street by this name but it is in the Docklands and not in Hampstead.