You can get a custom Enfield lefty now, but as far as I am aware, the service rifle was never made with a left-handed variant. Lefties learned to shoot righty.
Depending on where you lived, being left handed was considered weird or even evil (Sinister was originally just left sided (more or less)) so a lot of left handed people forced themselves to do things right handed, either by choice, or by strict instruction in schooling.