You've probably already seen it but on the "good garages bad garages" thread someone has recommended Ian Knight Automotive in Bury - 01706 830313. I have also used Mangoletsi and Lythgoe in Rochdale when in the area, which are both franchised dealers. You could also try Ferdi's in Lytham - 01253 738903 or Albertos in Mossley (don't know the number offhand).
Can't help massively but I have used Lythgoe in Rochdale which although it being a main dealer is not too bad for service. DO NOT use Lythgoe in Bolton though. I would hate for anyone to bother their a*#e on this place as they certainly won't bother theirs for you. But the best bit is when I mentioned it to Lythgoe Rochdale they dramatically reduced their price for me, so they are certainly worth a bash.