HI,
Yes, I am aware of that patent and have researched the ones it cites and ones cited by those too and still no sign of the straight mu-follower itself. The patent you mention does mention the mu-follower but gives no clue as to who invented it. I have been told it may have been described in an old Wireless World so I am pursuing that route too.
I have found what appears to be a patent for the SRPP but nothing that resembles the mu-follower. As you say, I am sure it was not called the mu-follower at the time it was invented.
Cheers
Ian