Thanks John.
So of the 3 carb bodies I have all are stamped 30T on the bottom.
The top stampings are 39, 28, and one possibly 28.
Oh well .... I'll keep my eyes open around the jumbles for a 45 then.

The knowledge in this group is amazing thanks so much👌

28 is for 13/16 275 smaller type carburetter. 58 is for bigger carburetter 1 amd 1/8.

Thanks John. I'll keep looking.... I see Amal are selling new 276C/1B's.........