Cavendish Avenue: music room - February 7, 1967.

Paul may have owned the house at Cavendish Avenue for almost half a century, but he has been fairly canny about allowing pictures of the interior to appear in public. It's instructive that even in the day, he was the only one of them who didn't allow Beatles Book Monthly photographer Leslie Bryce in. And so it has continued - anyone attempting to use Google Street to get a look at the exterior of the place will find it's been removed at JP's request...and fair enough, too (although pictures of the exterior abound).
The most intriguing corner of the house was/is the music room, as those who have read the Hunter Davies biography will attest. That book has a famous section which remains the only vérité account of a Lennon/McCartney songwriting session, for "With A Little Help From My Friends", in (fairly obviously) Paul's music room. There are detailed descriptions of the room in both the Beatles Monthly and the Davies book, but being a little bit older and a little bit slower, I hadn't connected them with these fairly familiar photos of Monkee visiting Beatle on February 7, 1967. However, the ones immediately above and below were taken in that very location, in front of the Paolozzi sculpture (Solo, by name).
The music room was/is on the top floor at the front of the house overlooking the courtyard. Back then, in addition to Solo, it was home to Paul's hand painted piano, broken stereo equipment, records, and a large triptych of Jane Asher. How it looks these days is anyone's guess, but nothing like this (or that) I'm sure:


Three days after these photos were taken, the orchestral session for A Day In The Life took place at Abbey Road, attended by the Monkees, amongst others. Mike Nesmith was staying at Kenwood at this time, having taken John up on a casual invitation made during the Beatles' 1966 tour of the States, much to John's initial displeasure.
These may also have been taken in the music room: