I have had a message concerning a strange unidentified and unfamiliar bird song/call heard from a thicket by J.32 Coryton by someone called Jonathan Harris and forwarded to me by GBC member John Aggleton. Jonathan did two recordings the links to which are below. They are stored on our Google drive so these links should work. The recordings are .wav files. Turn the volume up – it’s a piping call on some occasions with a descending trill at the end
First one: click here
Second one: click here
Glamorgan Bird Club 
I can’t think of anything like that calling from a thicket other than ??? a Eurasian Jay mimicking calls of another bird. Undoubtedly a long shot and I wouldn’t put money on it!