Just a long shot: my mum had this horse as a youngster and my 12.2hh pony was his personal babysitter.
Merlin was a IDxTB, 15.2hh (or might have been bigger) bay gelding - registered name Beverly Grand Finale.
Was sold to a member of staff but due to other circumstances she had to sell him on after a few years, always wondered what happened to him!
He had a small white star, a sock or two. His most defining feature was that he was a S**T in the stable or on the yard - fab under saddle and I used to ride him when he was a 4yo, but getting tack or rugs on was a battle. (Was sold off our yard for picking a child up over his door!!!!!!)
If anyone knows what happened to him - he'd probably be around late teens now.