I can remember a C172 and one other light acft being based there within the last 10-15 years. Not sure now.
I got involved in the consultation process with Dacorum Council as whoever was involved trying to start flying there again was involving Luton in some of the proposals without asking first! I seem to remember gliding was one of them.
Bovingdon was closed by the RAF in 1969. I don't ever remember Shackletons there. I went there shortly after the filming of Battle of Britain when the Heinkel 111s (Casa 2111 really) were parked there. Crawled all over them. Ah, nostalgia isn't what is use to be.