Kenwood: 1913 - part 4.

The final part of T A Allen's 1913 plan for Kenwood (click on it) is a cross-section of the house, which shows the two-level design. Kenwood is built on the crest of a hill, and the split-level approach was also used on the first floor. In the attic, the raised section to the right corresponds to the tank room, where John's cats were housed. This is actually behind the top floor room with the large window, where, of course, the studio was situated.
I've done a bit more digging on Mr Allen. The Kenwood (or Brown House) job was relatively local, as at that time he was living in Surrey, in the village of Normandy, occupying a house called Lynethorpe. Allen was actually the son of another architect, also called Theophilus Allen. There are records of him being employed by Norman H Johnson (who originally commissioned the plans for Kenwood) prior to 1913, so it's quite likely there is another house in the area designed by Allen for Mr Johnson.
There are a few other buildings that are known to be Allen designed, eg the Worthing Dome, and, most interestingly to those of a Kenwood bent, Oak Hall in Haslemere which dates, according to the plans I've seen, from 1911. You can read a potted history and see interior photos HERE, and if one of these pics in particular doesn't immediately make you think "living room at Kenwood", then you haven't been paying attention at the back. Allen clearly had a thing for panelling.
In the register of Architects at RIBA, he is listed close to another such, who happened to live on Merseyside...somewhere called Mendips. (True! But not that Mendips.)