I've used Sytner Oldbury a lot and I've had no issues whatsoever.
If you do decide to use them,even though the service department is quite well run,I would get there before the early morning rush.
However,due to moving work locations,I'm possibly going to use Rybrook Worcester (just off J.6 of the M5).
My first dealings with them did not go well.However I have spoken to the service manager and these issues have been ironed out.
I shall probably be getting them to service my car and see how this goes(I've just got to see whether they will accept oil purchased from Opie!).
I presume you know that you don't have to go to a main dealer to keep your warranty intact as long as any indi definitely uses oem products.Due to this,have you thought about this company:
I've not used them,but I've heard some good feedback.