As far as the UK CAA are concerned, you can renew an expired PPL with just a medical - you don't need a class rating to renew the licence, provided your latest CLASS RATING has not EXPIRED by more than five years.
You do need a valid class rating, of course, to USE the licence once you get it.
A guess here - if CB's LICENCE expired in June 2007, he likely took the skill test in (June?) 2002. That would give a class rating valid until )June?) 2004. Five years from then would be June 2009.
If my guess is accurate, get a JAA medical, go to Gatwick and renew the licence (walk in, do it on the day). then complete a proficiency check with an examiner when he feels he is ready to tackle UK airspace and R/T again. Licence page signed there and then on successful conclusion of flight.
If he's in current flying practice, that's all there is to it.
If my guess was wrong and his latest class rating was signed more than seven years from the day he applies to the CAA for renewal, then he will need medical and class rating test BEFORE application (and a larger fee to the CAA).
CB - you looked in LASORS you say? Have another look at Scetion C, page 19.
http://www.caa.co.uk/docs/175/Sectio...%20LICENCE.pdf