I used to visit an Aunt in Quinton years ago, so know the area a little, if I remember she had trees in her back garden but it was pretty built up otherwise. Could the bird be moulting I wonder as our blackbird and robins are now. Our sparrows down here on Anglesey are just about still breeding but most of them are coming to the end of their season now.
Lot to learn
Hi Natalie, great you've got Bullfinch around. I believe they are quite late nesters, (one good reason why hedges shouldn't be cut early!) so he may have another brood still in the nest and is making contact calls to his mate. They only visit my garden these days to take Amelanchier berries, and though I can see the male well, the female is often camouflaged in the tree!