Sorry to differ on this, but I know PARA Battalions received the L1A1 Self Loading Rifle in 1958 after the washup and return from Suez.
Some units got an earlier version believed badged FAL.
It was then adopted at RMAS Sandhurst for all entrants in 1959 by our very own famous WO1 (RSM) Lord, Parachute Regiment, who was seconded there and showed off his prowess for the drill instructors manual of that year. The Guards Depot saw the very first FAL adopted as L1A1's in 1957. I have also been told by those that were there, that after Winston Churshill boshed the EM2 rifle the L1A1 was hurriedly brought into play.