Hi, Many thanks for your replies I've had a look behind the ABS valve block and found what seems to be the round grommet! It looks around 50mm in diameter? Theres a smaller 25mm circular disc shape higher up but this looks more like a moulding in the bulkhead. I cant physically touch either to confirm they're rubber, even tried getting a photo, but cant get near enough as they are both quite obscured with the coolent expansion bottle etc. Did you drill it from the engine bay or guestimate it, strip down the glove box and surrounding areas and drill it from inside the car. Once again thanks for your help Dave