Hi Valda,
It looks as if it is most likely to be Harrow on the Hill, although it could I suppose be the one in Pinner. I emailed Harrow local studies library yesterday, and am keeping my fingers crossed that they can help. The family papers are, I suspect, a mixture of fact and myth, there is a family tree which comes from either a sister or perhaps niece of Thomas White's second wife and letters written around the 1900s from someone born in the 1860s quoting something his father told him. I can't thank you enough for all your help. I really appreciate it.
Best wishes
Philippa