I’ve seen some birds showing signs of this in my garden in Bleadon, N Somerset too. I have also seen it previously (a few years ago). It doesn’t seem to have had too much effect on the numbers I see though, unlike the nematode thing that devastated the greenfinch population. It also didn’t seem to affect other species.
Is there anything we should be dong to help with this. Cleanliness at feeding stations is probably extra important just now. I’ve not seen birds that are sluggish and hence could be caught eaiily and treated.
I’m afraid that due to technical problems the earlier posts on this subject have been lost. My apologies!