Thanks for the kind replies eveyone, the AA have just left.
The problem is a blown fuse. On the side of the battery the two live wires are fused in a small red box, and its this that has blown meaning the no power is able to pass from the battery.
The AA man couldn't give an explanation as he said that these fuse usually 'take some blowing!'
Anyway... I've decided to keep it here overnight and the AA are collecting it to go to my local dealership tomorrow, Im glad in a way that its something as simple as a blown fuse but also worried as to what caused it...
Obviously the fuse must have blown while I was last driving it... therefore Im guessing the problem could either simply be a defective fuse or maybe the alternator was not regulating the voltage supply properly going back into the battery, causing it to blow...
Fingers crossed its a quick fix and I will have it back tomorrow night, but I think I might invest in a spare fuse just in case... these things dont usually go for no reason.
One thing that is good though... the central locking system bypasses the battery meaning Im still able to lock it...