If they're anything like our (fleet) Transits, they get raped everywhere, infrequent servicing and repairs, and generally not looked after or loved. I'd NEVER buy an ex-fleet van!
Plus trust me, the one piece rear door is an absolute cunt. I'd much MUCH rather have a twin rear door!
(also, nearly all fleet Transits are FWD, not RWD, now. All ours are, and I'd suspect the RAC are the same)