Update folks.
Walked in and waited at least 20 minutes for Adam to finally come and sit with me.
Apparently there's no 7 day cooling off period.
Anyway... I have to, apparently, allow them to sort out this situation. Which means give them enough time to find the book on their site. The valeting bay has been torn apart - it's not in there. The girl who part-ex'd it has said the last time it had a service (2009 it would appear) she didn't get the book back. That means it's in a vast expanse of other service books (all being well) in some cupboard or archive somewhere on site. I've given them until tomorrow afternoon to find it that way. If by this point they haven't found it, then they have to contact Head Office to obtain the details of the previous owner on the log book to find out where it was serviced - in which case they can then get them to fax a copy and get the book stamped (in an ideal world).
As per their procedure I have to allow them to do this. They're quite reluctant to go down the Head Office route as they'll get a bollocking for part ex'ing a car which doesn't have a service book. Anyway, like I said, if the book doesn't turn up blah blah blah.
I've advised them not to sell my car. Strongly advised. I said I was sick of the whole thing it'd been a farce from the outset and that I'd much rather have my own car back - to which they said it's not that simple as I am now registered as the owner of the black one. I said, "Yeah, it's about as simple as asking me to commit insurance fraud!" LOL! He looked very sheepish at that and said "Yeah, that was naughty."
Anyway, I said if it doesn't turn up, and they manage to contact the old owner, if he says it hasn't been serviced then I'll be getting my own car back. If they don't manage to contact him then they're planning to contact dealers around his postcode. One step ahead, I wrote down the postcode of his address so I'll search local dealers and ring them myself. That way if it's serviced this whole sorry state of affairs will get sorted quicker.
They're very aware not to sell my car (R27), they're aware I haven't sent off the DVLA slip, I now have the cheque in my hand (I'm not cashing it) and they have timescales to sort this and will contact me daily with an update.
I'm currently writing to Evans Halshaw Head Office, and CCing my contact at RUK.