Best place BY FAR in glasgow is Rub-a-Dub on Howard street, kinda behind St Enoch Square.
Map here:
http://www.rubadub.co.uk/?node_id=1.5
They've done all the decks for me / The QM / Bamboo / The Shack (rip) for years and always got them set up beatifully. They're specialists and the only people I know who service decks who actually
use them, if you know what I mean. Also, it's a really cool shop - if you haven't been in before, you'll like it a lot.
If Dundee is more convenient try Gordon at Sounds Inc; email / phone no / web form here:
http://www.soundsincscotland.co.uk/contact.html