Thanks for replies AJShep and BlackCat. i didn't mean to sound dismissive, it's just that no one has ever mentioned raw diets before and my experience has been that giving Alfie a big variety of foods in the early days did him no favours. I would try, but all the advice here seems to be not to keep changing the diet. He is mostly perfectly perky in himself, apart from when he had the bacterial infection which made him quiet and lethargic. But he must be in fairly constant discomfort.
He has been wormed with Stronghold regularly since we had him and he has had faecal tests, that was how they picked up the Campylobacter. We haven't had blood tests yet but that is their next suggestion. I have been to the vets with him 12 times over the last 6 months.....

I am now so confused, I hardly know what to do...... but thanks for your support. This is the first time I have had any support with it at all really.