[jack404]

Jonty G'day, those BL locks had a spring sorta like the pic below

the hole maybe have been a round section or just a square end with a hole in it

not hard to make by any means if you get the idea on how it was fitted

if you reverse your pic the spring sit's as drawn

cheers and good luck ( sorry for the scratch pic but you'll get the idea)


next pic is the insides of how that period locks go together to show you what may go where (or whats missing)

jack