Had my rear discs and pads changed on Friday.

This afternoon...and on my first proper drive of the car since...electronic handbrake warning light comes on...unable to apply parking brake.

Some sort of calibration issue, perhaps? I am told my new discs are thicker than the old ones. Is there a hand-brake reset procedure that could fix this, or am I (once again) heading back to the garage?

Thanks!

I believe it goes like this...

Start the car with the parking brake off.

A message should come up on information screen between the clocks that says "apply brake while engaging parking brake" or something like that.

Hold your foot firmly on the brake pedal and engage the parking brake.

That should do it.

^ ^ ^ ^ ^ What he said, with a tiny bit more info; to start with the Parking Brake off, first stop the engine without setting the brake, as there is no way to disengage the Parking Brake without the car on or running.
This worked for me also.