I have spent a day going through my model books from the 50s / 60s trying to identify it for Mick and the nearest I got was a Chris Craft.
DickyD is right in saying that it does look home made, it maybe a prototype of a model design that never made it to production, I have a Vic Smeed prototype hull in my collection which never saw the light of day.
All I can say to Mick is that this could be a “one off” and therefore unique so it will always attract questions whenever it is sailed.