I’d love to answer like this: "Thank you so much for your generous offer to cook me dinner in the unlikely event that you catch one but I’m sorry, the answer is no. Once when I was young I had a bad trip on acid and in the course of the 38 hours or whatever it was I went to a seafood restaurant. I had red mullet. And my hair was also red and it was a mullet. And it’s just seemed to unsettling to eat fish since then. But thanks.
“There was a point to this story, but it has temporarily escaped the chronicler’s mind.”
Edit to add: I’d just like to give them an answer that is as ridiculous as them asking if they can disregard our rules/lifestyle/homes. Apologies for the obtuseness. Douglas Adams is probably more obtuse than UK vacuum ads.