Theres a good one at Blackhall on the Queensferry Road, the owner is an ex BMW trained engineer and gets good reviews, my boss takes his one series there. It is tucked away through a very narrow archway, so don't be put off by the first appearences.
http://www.villageedinburgh.com
Garage also gets a mention on this thread http://www.z4-forum.com/forum/viewtopic.php?f=2&t=40617&start=15 also gets a few other mentions from other members over the years if you use the search function :wink: