If it helps, I believe this was just a conversion kit for Lee Enfields to 7.62mm and not a whole rifle.
From another source... See a reproduction of the parts layout from the Sterling 7.62 brochure on page 40 of Ian Skennerton’s S.A.I.S. No 18 " 7.62mm L42A1 SNIPER, L39A1, 2A & LEE-ENFIELD...