Thank you both
Ozzy had diluted urine about 2 years ago and I asked the vet if drinking more would make it diluted, because this made sense to me, but she said no.
Although at this time the urine did right itself, after he had loads of blood tests etc which came back negative.
I think he was drinking more because he was on Bakers dry food (this was before I knew better) and when I changed his food he stopped drinking so much.
He was not on Metacam then so that is why I am now worried.