25k a year is going to kill the cars value anyway, so i wouldnt bother going to the expense of dealer servicing for the sake of residuals.
However if you are a novice then i would reccomend you getting it serviced at a dealer or an independant, you will be relying on your car for work i presume, you dont want to miss something critical.
The haynes manual will give you a break down of what needs doing when.Modern diesels dont need as regular changes as before, some even do 18k between changes (VX's iirc), as long as you use good oil and filters, theres no real need to better the manufacturers reccomended.What kind of driving is it likely to be?