I'd say check the kill switch wiring and that it's not in gear and other obvious things like that. Sidestand switch? Check around the bike for anything else they might have done. Doesn't sound like they're very good at what they do so anything may have been played with. Is there a switch connected to the clutch? I assume so as you have to pull the clutch to start it but don't know if it's on the lever. If you've repaired the wires so you've basically got the same cross sectional area of wire all the way it should be fine (Not reducing the cable size I mean) although I wouldn't keep bullets if they can be pulled out. You can get straight through crimps which should be fine.
Edit: Just read Hovis thing about the clutch lever.
You might have the two reds the wrong way round and it wouldn't necesarilly blow a fuse. A fuse blows when there's too much current.
Let us know what you find.
