For those who have expressed an interest in the health and happiness of my felines. Percy was OK with his stitches until about the 15th: then he started pulling on them, and we had to fit him with one of those plastic cones that attaches to a collar, and stops the wearer reaching his/her flanks. He put up with this with a better grace than I had expected, but he kept hanging up on things - door frames, chairs and such, when the edge of the cone turned out to be a bit wider than he had expected. However, he was pretty manoeuvrable, and even managed to jump the back fence with the cone on his head, in order to fertilise our neighbour's garden - he got back safely, and our neighbours don't mind him, fortunately.
We finally got the stitches out, and the cone off, on December 23rd. Percy is now a much happier cat, and life has gone back to normal. Mungo has also made a good recovery from his vet experience, and my credit cards will recover eventually.