I have used on several occasions, Robbs Garage in Wallasey. http://www.garageswirral.co.uk/
They have done a few for me, Galaxy Tdi, Merc ML and an X5. NEVER had a problem with their work. They are "old school" but also have the equipment needed. I watched in awe as he opened up the valve chest from my galaxy, tipping all of the components out, before cleaning, testing and replacing seals and solenoids, and then putting it all back together WITHOUT a manual, and then hooking it up to the test rig and it performing perfectly...
They have also done a "powerflush" fluid change for me on a few occasions, which has transformed the box.
Highly recommended from me. Oh, and the have always provided me with a free (auto) courtesy car.
Mike