Good question! Following trials at FVRDE some 20 examples, five LWB and 15 SWB's, were ordered for troop trials by the MOD. These were heavily modifed from the normal Gipsy, with a longer chassis, an extra fuel tank and other smaller items such as military lights and a NATO hitch and socket being added.
Little is known of what trials they underwent, although one LWB was dropped onto the dockside at Swansea Docks when being loaded, smashing the rear axle in the process. No one really knows what happened to the other 19, although it's believed they went to North Africa at some point.
An exact number of how many are left to this day is hard to say, although it is believed that just one LWB and seven SWB's still exist, although only one of each version are in their original condition.
An interesting find anyway and another which I can add to my Gipsy spotted list :-D