In reply to Indy:
I tried an Aeron at work for a while and really didn't get on with it. IIRC there are different sizes available however so I perhaps didn't have the correct size. (FWIW I got a 'Steelcase Gesture' ergonomic chair instead, which is superb)
I'm a fairly regular JLP customer, particularly for their electrical items. Great service and if there's ever an issue and I need to return / complain, they always do the right thing and give a full refund or replacement, no questions asked.