nessy, about 1/5 of the fish I catch when I'm catching bleak (using a net), are yearling roach (
Rutilus rutilus). Those should exist in Britain too, although they also contain thiaminase. And then there is the Eurasian minnow (
Phoxinus phoxinus).
Edit: And stupid as I am, I just made a new post despite just having explained how editing works.
abcat, this is the kind of situation where one would use that banana.