So, my car is now 9 months old and yesterday (Friday) it went to Beadles Maidstone for its 2nd service at 20K (3 free services). Good and efficient service from the dealership in their new showroom (old Audi one).

I discussed what was to be changed at this service. Included was the pollen filter but I had to pay for a fuel filter. I asked about the air filter but was told it was a very high mileage before that was needed.

It does seem that with the servicing in the first 3 years it is tailored for company cars to keep costs down but I am not sure that it does the car any good in the long run.

I've seen back to back Dyno runs with a manky old OE filter and a free flowing K&N on a PD engine, the difference was 0.x bhp or well within the variance in back to back runs that you'd expect. The simple answer is an air filter change isn't required so they don't do it.