She had another bout, which of course was on a Sunday evening, so I took her to the Emergency vet. They gave her some antibiotics and then the following week I took her in so see my own vet. He did full blood tests, which were all reasonable some were VERY slightly higher but not bad for her age. the others all normal. He did a sonar of her bladder which showed nothing that would cause a blockage, and just a very slight thickening. He did Xrays and her hips were fine but her spine was very arthritic (he said they call it bamboo spine. He then said he thought maybe because of the pain she wasn't crouching properly and emptying her bladder fully. Since she had been on antibiotics he said it would be a waste of time sending off a urine sample to be cultured.
She is now on one DROP of Metacam a day. I can't believe the difference. She is walking far more upright than she ever has and can easily jump on the bed. She is practically blind, but since I don't move furniture about, and my garden is fully walled she is able to get out and about in the garden and the house.
I happy with that. Re my knee, I went to see an Orthos, there is no arthritis in the knee and everything looked OK (he said V.good for my age :0) he thinks it might be a stretched ligament. He gave me an injection into the knee and it has been somewhat better. At lest I can walk more normally now