Circuit rules, not TDO. Similar thing happened the other week at Cadwell on a No Limits day. I'll not name names, but she'll read this I am sure. 
  Cost her £5 for a phone call to DVLA  (on Saturday) to get the Cat A verified. Even though No Limits knew well that she had Cat A they had no choice in the matter. 
 MotorSport Vision Limited own both circuits.