Electronic Brake Distribution (EBD)
A classic example of RTFM. The 'electronic diagnosis' section of the GTV/Spider workshop manual states the the handbrake warning light and ABS light on together indicates a fault with the EBD.
OK - so I don't actually know what's up with it but I've just ordered a VagCom cable in order to try and see what the ABS ECU (Bosch ABS 5.3 in my case) has to say for itself.
In the meantime - do any of you know of any common faults that cause the EBD to fail.. e.g. a dicky speed sensor on the rear wheel?