Geoff,
I remember buying a replacement H&K box whilst serving to replace a shot out kit via Donnington, and I believe I had glimpse of an invoice at £4500 to MOD. I was offered a H&K complete kit last year at £2500 from a southern dealer who happened to have it on the shelf when I started this whole thing with Peter Sarony at Armalon.
Yes I could have had that kit knowing it was a proven L1A1 additive, but decided to help him out with John Clark to keep his business going for one, albeit he is busy anyway, but also to get the best, and someone you can always return to, to get a personal answer, and a finer craftsman you will not find!!