I too did them in Glasgow and it was ****ing annoying. However if you look at all the crap they send you when confirming your booking there is a get out clause. I quote
'Whilst every attempt is made to ensure reasonable comfort in examination halls, the CAA cannot be held responsible for extraneous noise or for any breakdown or fluctuations in heating, lighting or ventilation facilities in examination halls which are operated on hire or lease arrangements and over which the CAA, as a result , has no direct control'
I think that covers them. By the way which one did you fail - instruments was the one that got me!!