A few years ago I regularly had a problem with the A/G service at a certain Kent airfield that styles itself as a London airport (despite being on a mudflat next to a nuclear power station a good 60 miles from the capital). On some occasions it was like listening to Heathrow Final Director. It wouldn't have surprised me to be given vectors. I don't visit there anymore.
Overall I think that P_S's approach is best. First of all, if you are confronted with a unit that is behaving above its station either politely comply (if it is good airmanship to do so) or ignore it (but announce your intentions for the sake of the other a/c on frequency).
If things get any worse (at the aforementioned Kent airport I was once berated on air for not doing what the A/G said despite announcing my intentions), a simple polite call of 'Station Calling, confirm your callsign XXXXX RADIO' with a follow-up phone call on the ground to tell them what you think!
If you still get problems after that, contact the CAA and NATS - A/G units and AFISOs have senior NATS ATCOs allocated to them to oversee their standards and would be very interested to hear about what units for which they have responsibility were up to. Certain members of pprune's ATC community do this job!
cheers!
foggy.