I thought it only fair to update everyone on the outcome of this story: having researched the fault on a few forums, I concluded that it would be sensible to try replacing the flasher relay unit. A local garage did this for me, for just under £50 including part and labour. The fault has cleared completely. After a couple of rather stern letters, the Director of Business at Cardiff Audi saw my point of view & refunded me in full
Thanks to everyone that contributed - forums rock
