> he also said he would not have considered the op option if he did'nt think she was up to it
That is a good sign.
I can understand you thinking about the option to have her PTS - it is something you are thinking about for BB, not for you.
I had my 14&half year old dog PTS 4 months ago, the vet wouldn't even consider doing any tests to find out what was wrong with him as age had taken it's toll badly and he had no quality of life, treating him for anything revealed on the tests would have only dragged out a an existance for him - not acceptable by the vets or my standards :(
However, if BB is enjoying her life and the only thing standing in the way of a decent quality of life for an oldie is this infection that can be treated with the op, then putting her through the op seems like the best thing to do.
Thinking of you and BB
xx