However, I had already ruled out such a possibility.
I have also ruled out the Americas and most of Europe.
Imho, while we don't have a certain answer, nothing is completely ruled out.
An attempt for answer:
Kenwood, St. George's Hill estate, Weybridge, Surrey, England
Reason:
The clue picture is clearly a cover for "Yellow Submarine".
Another sort of clue was "Let it Be"
And another clue: it's related to a person that is dead now.
So, the Beatles. Maybe John Lennon? Almost everything is in NY and Liverpool
But this house seems to have been a big part of his life (and death).