For a few months now the boot central locking on my GTI had packed up. I thought it was the lock actuator and ordered one, only to find that this wasn't the problem. So, after trawling through some threads similar to my issue, I discovered that it could simply be a split in one of the wires powering this mechanism.
Lo and behold, after pulling off the rubber boot at the top right area above the parcel shelf, I find the blue wire had split, with the brown on its way too. I disconnected the battery. I then used a wire connector to repair the blue one and some insulating tape on the brown. With battery re-connected, I gave the key fob a try.
It worked, woo hoo!
In the past such forums have proved invaluable to me in diagnosing and rectifying numerous issues with my cars. Keep up the good work people.