Kenwood: dining room, 1965.

The location of the 1965 family shots of John, Cynthia and Julian can now be definitively established, thanks to the above, uncropped photograph. Although it's not perfect quality, the two framed pictures can be seen clearly enough to establish the identity of the right hand one; compare with the following, sold at auction in 1996:


In fact, both of the reproductions in the first photo were sold by Cynthia in the same auction as a job lot. They are in the style of Basilus Besler, and, obviously, have a botanical theme. Here's a closer look at the visible portion in comparison - clearly the same picture:


We can pinpoint this as the dining room thanks to the note from Cynthia which accompanied the lot, stating that the pictures (which are actually colour) were originally bought by Ken Partridge, and were hung in the dining room. Estimate in 1996? £150-250.
Many thanks to Jeannette and Lynn Mayes for tracking the uncropped picture down.