They're all '54 models with a one year only 'non-barrel-shaped' full width hub. Fitted to the rigid and sprung singles and to the twins.
See catalogue (Matchless) pic from '54. Couldn't quickly find an Ajay one, but it's just badge engineering.
My own '54 500 twin (Ajay) has the same hub / brake. Prior to that, single-sided.
In Matchie speak G3L = rigid and G3LS = Sprung, and Ajay equivalent were Model 16M and 16MS at 350, (or G80 and M18 et 500).
Last year of the rigids (I think - but IKBA about the singles really).