My partners 2011 diesel has now done 201,000 miles. The last time it went to the dealers for a service was over 3 years and 90,000 miles ago. I've done all the servicing since then. Oil & filter change every 10,000 miles. Air & pollen filters every year. Fuel filter every 60,000 miles, gearbox oil change every 90,000 miles. Most important, taking the wheels off every few months and checking the condition of the brakes, and replacing discs and pads when necessary.
If you can get hold of the service schedule, figure out what jobs you can tackle yourself, try and find a trustworthy garage to do the jobs you don't want to attempt.