You know, I would have bet money on the fact that i had read about someone eating fish and chips in one of the books, and I even thought I could remember the mention of fish and chip papers, but I've looked all through my kindle this afternoon and can't find any mention.
In Secret Trail Anne talks about fresh plaice from the sea, fried, and chip potatoes, but no-one eats any.
There are lots of mentions of chip potatoes in nearly every Barney book too.
It's something I could imagine Bill doing - taking the family for a fish and chip supper on the coast somewhere, it would be a fun thing to do and Bill is full of fun.
I can imagine him getting fish and chips for them as a treat perhaps when they had gone to stay with him and mess about at his old home in Valley - if they had ever got there, that is!!