our passat 130 tdi is due its service......128,000....with full history up till now

question is,should i put it into the ********?....they want around the £300 mark for a 40k service!
cambelt etc was done last service,so whats involved in a 40k service?...seems steep to me at £300 for a few filters and oil change or is this about rite?
any help would always be aprrecitated
is it worth while doing it myself or sending it to a reptuable vw specialist i know who will change half that?