Robin,
About 6 years ago I bough the last ex military 'Molly' the Muir Hill A5000 Mk 2 from Withams. It was in excellent condition with only 1500 hours. I used it for a time, but then sold it to a collector in Ireland.
I kept it in good order & under cover. I also obtained the army operating information book/user handbook (Army code No. 22296 issue 2) which provides every details & image imaginable relating to these machines. It also covers the Boughton winch and the 'field training section'.
if anyone is restoring a Muir Hill A5000, I would happily provide a copy for a modest fee. (Lots of pages)
A couple of my pics added.