Craggenmore, you wouldn't be looking to instruct at Cabair by anychance?
I went for a job at Elstree about two yrs ago and as a self employed instructor they wanted me to have liability insurance. I investigated this,it was going to cost a bit and quite honestly you don't need it. I 've been instructing 3yrs,just started to examine,self employed and no probs.
I agree with DB6, once you let them go they are captain you can't be held responsible cos you not in the ac.