Unlucky dude, a guy I know was selling his car, and taking it from his lock-up to the MoT station, stopped off at his house to get the directions, and the car got clamped outside his house!
You can drive to an MoT centre without tax or MoT as long as you show proof of the booking, but the garage wouldnt do it as he missed the appointment, he couldnt afford the fine so the car got crushed! How annoying!