As a matter of interest my C3/M82/1200TX has a Canadian contract ZF69 scope in RALS4 rings.
From Parker-Hale's 1962 catalogue:
-first letter indicates type of mount, where "R" is for "roll off".
-Second letter is for the size of dovetail they fit, where "A" is for BSA & Brno high power, "B" is for Brno .22 rimfire & .22 Hornet, ect., "C" is for most .22 rimfire rifles.
-"L", "N", "H" or "Z" indicates the bottom scope tube distance to the top of dovetail, approximately .230", .330", .486" or .674".
-"S" or "X" indicates either Standard or Extra long recoil stop, (required on Brno rifles).
-The digit at the end indicates tube diameter, "1" = 3/4", "2" = 7/8", "3" = 1", "4" = 26 mm, "5" = 26.5 mm.
So the Canadian C3 Kahles ZF69 scope is low mount 26mm on
steel A22 and A28 type scope bases.