Thanks all - looking online it looks as though Honeywell bodies have an H stamped on the side?
I came across Myson, which looks like a possibility. Might try the local supplier
Moved into a flat where the previous occupant has broken off the heads of all the TRVs (thanks!)
All I'm left with is one of these on each radiator. It would be brilliant if someone could identify the brand so I can try just screwing on a replacement head....
One unusual feature (to my...