Do it yourself Steve if you are competent, and keep all the receipts in order, which shows a tidy mind, and the person buying your car will see that you have probably kept your car in a tidy order too.
As someone said, as the car isnt too new, it wont matter, but the receipts will show exactly what has been done.
A while back when we were selling a V6 Calibra with the Vauxhall service book all stamped up to date, we remarked about the full Vauxhall service history to the salesman in the Peugeot garage. He said not to worry about stamped up books, as they werent worth the paper they are printed on.
He opened a drawer and said "take your pick of about a hundred books" He also said that most mechanics if asked, would put a stamp in a service manual!
Dealers are scaremongerers in saying that your car isnt worth as much if it isnt dealer stamped. We have sold quite a few cars to dealers who have NEVER asked about stamped service books. It probably only concerns private buyers, but I am sure that loads of receipts for everything is more attractive to a prospective purchaser of your car than a book which if you have a mate at the garage he would stamp it for you, as the salesman told us.
These days, so many people mistrust some garages, who often skimp on the work (you only have to see programmes like "Garages from Hell" to see what goes on in bad garages), that car owners who have done the work competently themselves, are probably trusted more, especially if their car is very clean in and out, drives well and receipts and MOTs are kept in order.