Screwing back the fretboard? Why would they have to do that?
But yes, I have had bad experiences with shop 'M' also (not nice to quote names for negative experiences), and would highly recommend going to someone who will do the work on the spot for you. This way, you can ensure that everything is done to your expectations, with no surprises, and learn some things along the way to boot!
My personal recommendations are Mike (SV) and Beez for basic setup/rewiring work, and Malcolm for more complex issues. I would never ever leave my guitar in a shop, out of my sight. Just check out the guitar bags all leaned against each other at shop 'M', and you will know why I am so paranoid.