I recently purchased a Unipower Forester ballast tractor. It started it's life with the RAF and then was transferred to the board of trade, ending up at Heathrow. It finished it's days there in the late 1990's and the next owner kept it in dry storage. It has a chassis number of 450 according to the paperwork and the engine dates it to around the end of 1958. I've checked with the RAF for the original record card and this no longer exists. We are still a bit unsure of build date, although we know she transferred to the board of trade in 1962 when she was first road registered. I am particularly after any information about her, photos etc... and also an idea of the type of jobs she would have done whilst with the RAF and with the Board of Trade. Below is a photo of how she looks now.
The Unipower's RAF registration was 40AT79 and very close to Antarmike's old Antar.