This is in the UK not the US. In the US a business prohibiting a real service animal would face fines and lawsuits.
It’s technically the same in the UK many of the laws are the same it’s unlawful to refuse him service .
I don't see them In restaurants, ( healthlaws)or I would leave.
1/2 of dog owners give the other half a bad name. P.s. keep your dog off my lawn, that cheap dog food you feed them, causes wild onions and garlic to bloom where ever they do their businesses, and you can't pick up pee that destroys the grass and young trees it's been applied to
The problem is, of course, that US businesses prohibiting not-for-real service animals face fines and lawsuits.
Among many other things they can be sued for. Like not baking a cake for a gay “wedding”.