That photo looks like it was taken about a mile down the road from where a good mate of mine lives in Pewsey.....and he's owned a few ex-mil vehicles in his time including a Ferret and a 1942 GMC 6x6. He still owns a lwt Landie and a WW2 BSA WDM20.
The owner of that Quad really needs to get it re-registered with DVLA if he has enough paperwork for it? At the very least he needs to put some black and white plates on its now its at least under Historic VED tax class.