"but I wish it was better served by public transport!"

the H11 bus from Harrow bus station stops a few yards from the door.
the H13 bus from Ruislip stops a five minute walk away.
South Harrow would be two buses H12 and H11 or H12 and a ten minute walk.
And the Metropolitan Line at Northwood Hills is only a 10 minute walk (where you can be at Baker Street in half an hour)
Watford requires two buses H11 to Northwood and No 8 bus to Watford High street.
For Rickmansworth, you would use the Met line and change at Moor park.

Graeme