I need to find a quick release steering wheel as my customer is quite a big guy and we think it will be easier for him to access/exit the car with the wheel removed.

Does anyone have any recommendations?

McGill Motorsport do a few and I've used them in the past.

http://myworld.ebay.co.uk/mcgillmotorsports&ssPageName=STRK:MEFSX:SELLERID&_trksid=p3984.m1543.l2533

If I was fitting on another..........it would be this one

Don't bother with cheap rubbish, as dicussed on here many many times

http://www.plays-kool.co.uk/acatalog/WorksBell.html

+1 for the rapfix. Not locost but top quality.