The archivists at Solent Sky have just located some preliminary sketches and calculations from 1944 that appear to be early thoughts for Clifton's Technical Note 4040. Of course this was never a project or even truly a concept, just a note to show that it was theoretically possible to acheive vertical flight with a RR Griffon. Images on their Facebook page.
The VTOL prop planes with the pilot flying on his back never progressed because trying to land was extremely difficult. Landing an aircraft straight ahead is never routine, and these tail-sitters made landings dangerous even at a good landing pad. Lockheed's VTOL Test Pilot Fish Salmon was a close friend of my Dad's. I discussed the Lockheed VTOL with Dad in the 1980's after I'd started flying, and Fish had said that looking down over his shoulder and judging everything he needed to was just impossible. Landing one of these at an unprepared field likely would have been a disaster.