CAW:
I´ve just found this picture taken at Yorke Bay sometime after June 1982
I would be very surprised if that was in Yorke Bay - it was heavily mined with both anti tank and anti personnel devices, and it was a good few years before any clearance was carried out. If, however, it was taken on 29 Dec 82 it was of the only 'heavy' digger/dozer the engineers had on the island at the time. Whilst trying to dig out sand or gravel from a beach for use in construction they succeeded in bogging it down with a rapidly incoming tide and we were tasked to try to 'help' the recovery and prevent many red faces. The engineers 'reckoned' it weighed 16 tons, so even our Chinook was not going to lift it (although we did try - Op Corporate rules!). Eventually though we did succeed in helping to pull it out just before the sea would have forced an abandon ship episode.
Unfortunately I can't remember exactly which beach it was, but I seem to remember it was fairly close to PSC (Port San Carlos).
WRT Mexefloats - they were used for almost everything to do with loading/offloading ships in Port Stanley in the early days - even pax to and from accommodation ships such as the Norland as none of the port infrastructure could take the traffic. In addition the mexes got everywhere - I think we had one or two over at PSC (which was how the bulldozer got ashore in the first place).