When I visited London in 1984, I made a point of heading over to Kensington to view Peter Pan connected places in Kensington Gardens and also to check out if 23 Camden Hill Square was still there - which I am happy to say it was (and apparently still is) .
From what I understand, Jack's daughter Jane had a flat at that same address in the 1950s - she lived there with her daughter Henrietta. And Nico lived next door at 22 Camden Hill Square during the late 1930s and until his daughter was married in the early 1950s. 22 Camden Hill Square was apparently damaged during bombing in the war (I read that in Nico's letters to Mary Hodgson - which are great by the way). Was 23 also hit?