St. Martins Plain?
As to the CCF. When I was at school, I went on a Cadet Armourers course. On the course it was drummed into us that we should never call "The SMG, L2A3" a Sterling. I found out years later that the Government was trying to avoid paying Sterling any Royalties for the "Sterlings" produced at the Royal Ordnance Factory. So no change there then! (The British Government has form for this.)
In later years, SMG and Sterling were used interchangeably and indiscriminately by us all.