The flats are Farm Court, off Watford Way – Hendon.
Of the view through the gate, the subway is still there, as is the building to the left, but the building in the background has either been demolished and replaced or very extensively renovated. The Livemaps south view shows it wrapped in scaffolding but the east view shows it finished.
A free one for you! Just round the corner in Aerodrome Road is the garage from Randall & Hopkirk - You Can Always Find A Fall Guy.