Pprune comes through yet again!!
I looked at all the advice, checked out TheHangar.co.uk, and am know the proud owner of twin pristine pairs of David Clark 10-40s, with gel ear seals and about 100 hours on each set, at £250 for both headsets. So now I've got a DC headset and a spare DC, for slightly less than the price I would have paid for one DC headset new. Bargain!
Thanks for all the help!
. .AB