Well said, Ray. I am racking my brains....The only M I can think of is MCA of Aston, Birmingham, who, back in the day, were a well respected supplier. But, like Hepolite, a brand completely unrelated nowadays to their previous reputation, at least in the eyes of us oldies.
Snag here is that getting any sort of satisfaction will be difficult. For my money, Newman Cams in Farnborough, Kent is the place to get your bits. They are camshaft manufacturers and well versed in the foibles of vintage machinery. They can also reface, grind and harden your old worn genuine followers and work miracles on worn cams.
Trev...Very strange wear profiles. I would expect them all to be worn in the same way, or in pairs. The far edges are concave, as if the cam has been slopping sideways, allowing adjacent cams to contact both pairs of followers, then the major wear in one place, more to the foreground. Not as straightforward as it first appears.
Swarfy.