I know these are not the best of photos - the first one was taken through the front window, and wrens are tiny. But we've been seeing enough of them (or enough of one) around recently for me to have added their call to bird sounds that I recognise. It was enjoying sunbathing on the back wall in the intermittent sunshine yesterday.
C describes it as a little ball of feathers with a tail - but we have a little dunnock round at the moment for which the same description would be equally apt. Here it's looking somewhat windswept!
And we also have several distinct robins around at the moment, including this scruffy one which, I think, is a juvenile growing into adult plumage. I hope it's that and not diseased. I take good care to clean the feeders regularly, so I wouldn't expect it.