If it's the lock then you've got a chance to fook them off and put a delock kit on there. But I doubt it is, most problems with Golf/Boras locking turns out to be the solenoid
As for fluid, as everyone has said it only needs doing every 2 years so tell them to jog on. Same with the cam belt, and again with tyres. Suspension control arms, I'm not sure what they are talking about TBH but at a guess I would say bushes which turn out to be quite labour intensive sometimes. See if you can get them to explain what they mean or better yet show you. Exhaust centre bracket sounds like the part that bolts up undeer the middle after the centre pipe is hung on the rubbers. If yours is broken, a scrapyard will be the best bet for one (although I don't see how it has broken)
