Is the service history book actually missing?
I once nearly brought a car and they said they hadn’t got the service history book and were waiting for it to come in from the garage they had the car from, it never turned up . . . .
Transpired that by doing some research on the net, the car wasn’t from that dealership at all, and it had been a hire car somewhere els, obviously the hire company hadn’t bothered having it serviced or worse?
Not saying this is the case here, . . . i pulled out and didn’t have it, I’d want the service history book at least, if it’s been serviced it will be in there, I wouldn’t worry too much if it hasn’t been service every year as a lot of people won’t bother to have a service in the first 2 or 3 years of ownership!