Hi Dave
I don't know about Aberdeen, but I live south of Stonehaven near Laurencekirk and have been in touch very recently with a good garage in Edzell. Sam Mackay is the guy you need to speak to and he can be contacted on 01356 648364. This garage services all the landys from the neighbouring estates so know what they're doing.
Hope this helps.
Jim
Ps. I've just bought an old series 3 in bits and have been swithering whether to get the old 2.25l diesel refurbished, replace it with a 200Tdi or just pop it back in when the time comes and see if it runs. Any advice please?