Catheters are a bloody nuisance, even though I had a supra-pubic one, not involving my urethra.
It seems most catheters are in for ten days post-op, and maybe Dad’s is in a few days extra to fit in with the overloaded NHS schedule?
Other guys have mentioned an anaesthetic gel that they use, but no-one’s mentioned the name yet, and I can’t remember.
Ask at the chemist. I suppose Bonjela for mouth ulcers would have a similar effect.