buildersmate, it is only legal to drive to a PRE-BOOKED MOT station, you can't just say that you were going to the MOT station and thats the end of it, you must provide eveidence that you had been booked into said MOT station and you were on a direct route to there.
You say you got "pulled", how do you mean, as most people say pulled as in they got pulled while driving/riding, and they only have the power to do so on public property.You say that the bike was parked on private property, but was it at the time of being pulled?If it was on private property, then they have no reason whatsoever to charge you for no MOT.Could you please give more details of what exactly happened?