Our old Daisy had an aural resection on one ear when she was about 5 - she recovered well from it & never had ear trouble in that ear again (she's the only one of our Cockers ever to have persistent ear trouble) I also have a friend whose Cocker had even more drastic ear surgery at Langford Vet School to remove the ear canal completely (the entrance to the canal was then sewn up) I trimmed this Cocker for many years & the surgery obviously left her deaf in that ear but apart from that, she recovered well & lived a normal life free from ear trouble after that, so its worth considering if all other avenues fail. Its unusual though - she's the only Cocker I've come across to have had this type of surgery before.