Skennerton, The Lee Enfield, states that 35,000 No.5 projectors were made by two different manufacturers. I have found the manual to be harder to find and more expensive than the launcher or sight. The 15 page manual, dated 1945, issued April 1945 is titled:
"Instruction book for the
Projector, Grenade, No.5 Rifle, Mark 1
Sight, Grenade Projector, No.4 and 5 Rifles Mark 1
Pad, Shoulder, Rifle, Mark 1"
Line drawings show the launcher with the No. 85 rifle grenade.