Howdie. LivinLOS, I've got a 900 Blade and had same sort of problems getting parts and good work done. The guy at Chalong, as nice as he is, is not a quality setup. Check out this link
http://members3.boardhost.com/thaimotorcycle/ and look for the post by Toby about a good mechanic in Phuket on Sept 12. There's a couple of options posted there by Thomas.
For parts, I ended up getting mine shipped from Australia and will do the servicing myself. Red Baron in BKK has parts for big bikes but is expensive (stocks K&N filters). Siam Superbike also has parts but is slow answering emails, if at all.
I called into the rental shop out of Patong en route to Karon 3 days ago and asked if he did work on bikes other than his own. Answer was no.