Whilst always using TMA to scope out a visit away from home for some inexplicable reason I’d never check closer to where I live – so having rectified this I had to visit The Hare Stone which is a couple of miles away.
Whilst in the London Borough of Harrow this is in a leafy area with very little development. There’s not a lot of information about the stone itself which (if you look at pre WWII photo) has been moved in the last century or even replaced by another stone? The Hare pub is a listed building historicengland.org.uk/listing/the-list/list-entry/1079732 but no mention is made to the stone unlike the nearby Weald Stone which is listed historicengland.org.uk/listing/the-list/list-entry/1286172 (see separate TMA entry). The road and nearby woodland are clearly old and there is the ancient “Grims Dyke” nearby which seems to be Iron Age grimsdyke.com/grims-dyke-ancient-earthwork-of-harrow-between-myth-and-history/
The stone itself is sarsen and there are a few of these in other places in Harrow including Pinner Memorial Park.
In summary an interesting stone to see if you are in the area but no evidence of it having any specific ancient role.