Regarding the aftermarket alarm, I've decided to get it removed as it's more hassle than it's worth. The fact the other guy bypassed the fuel pump relay has made the aftermarket one redundant, and it will only work as a siren...the original alarm/immobilser is doing some of the work too. Basically I got a hybird alarm lol. Plus it looks crap in the engine bay.
So the car is going back in next Saturday to get a new switch fitted, the aftermarket alarm removed and the original alarm/immobiliser properly reactivated. Then he will take a look at my dodgy interior light. I'm well chuffed now I know that the car is going to be better