Yes it [Heathrow] would have been built there, in 1946 it was ideal. The problem is not the location: on flat land, 20 mi. west of London, 6 rwys already there (built by the RAF), on a trunk road, room for expansion, etc., etc.
That's a novel take on LHR's history, probably just as well that debating it further would be a bit off-topic for this thread.
