Watched this flight on FR24 holding for ages just off Hastings, this morning.
The Argus article on TCX1638
CLICK HERE
What I heard on the approach conversation.
"Said he anticipated a normal landing to 126.825.then when he went onto 118.950 he told app that cabin crew had just said a piece of the aircraft had just fallen off which was poss his problem!!..it looked like a piece of the wing flaps was missing as they went down the approach.and twr confirmed that a piece was missing by the overwing exits as well??"
What may have happened was a noise or airframe vibration alerted the pilot to a problem, resulting in turning around over Belgium.
No emergency Squawk but needing to go into the Hold to burn off fuel.
Then on approach with the speed changes and flap configuration the item was disturbed and fell away.
Just a thought, anyhow I shall look out for this in an up and coming AAIB report.
Glad they landed safely and that no one on the ground was hurt, as I think we would have heard something by now.