57 Green Street: Flat L.

Despite lysergic dreams of communal living in 1967, the only time all 4 actually co-habited was in the autumn of 1963, at number 57 Green Street in Mayfair, central London. And yes, you guessed it - massive renovation means that this place is almost completely unrecognisable, making the auld then unt nau-ing almost impossible.
However, tragically, I have nothing better to do today, so hier ist der guff; fireplaces may be ripped out and renewed, but the locations don't tend to move about, so it's probably safe to assume that the above correspond.
The famous photos of fan-mail-openage would have been taken at the other end of this room. Note the bit of wall above the right hand red arrow - back in '63 there were 2 rooms here, with the far end forming a small dining room next to the kitchen. That section of wall "hanging" from the ceiling is what remains of the division between the living/dining rooms:

I think the record player would have been in the living room, and the windows seem to correspond:

As does the brick edge visible outside the window. Note too how the '63 ceiling has gone, so to utilise what would have been attic space back then and create a more "roomy" room:

If that's a blind, then these may correspond:

I'm pretty sure these don't, though. The modern one is an en-suite off one of the two bedrooms; I'd guess the '63 shot was taken in the small central toilet designed for communal use (though one at a time, gentlemen please):

Or.................................................................................not.