Ok, I got a reply from BirdsEye. Sadly it appears that the person that responds to customer care queries has no sense of humour, sending back a dull and fully “corporate” reply which I won’t bore you with.
Basically they told me which chains bought their range and gave me telephone numbers to call if I wanted to take it up with them. I didn’t. But I did notice a self dedicated to the Bake to Perfection range of fish appear in Tesco this week! Hurrah!