We've had the results now, and it is nothing to worry about (phew!). Two blood tests confirmed the protein, just a sort of early,warning to adjust his diet. He is already on senior wet food, but he has some adult kibble, so we will change that to a senior one too (TBH we get our dog food online and delivered, so had a bag to use up). Also the treats will be changed and I'll hunt out some low protein ones. Tonight he's got raw carrot, which he loves, so just some changes will sort it. The vet isn't worried. I'll take his last bag of adult kibble and the treats to the dog shelter.
He'll be 9 in June, vet says he is in good shape otherwise. 🐾