Okay. I have a confession to make. We normally try not to google in this game, but I couldn't stand it so I did.
I think I know the answer, but I'll wait for the rest to chime in.
Perhaps someone from the UK or a REALLY serious guitar freak from the US may know it, but although I know the person HM has played with, I think even that person would not be be readily recognized here-- perhaps his name would be slightly familiar. Yes, the man he played with was huge in the UK, I'm going to bet that no one here knows HM.
But let's see if anyone else wants to take a stab at it.
Hey, I could be totally wrong about my guess!!
Anyone else out there from the UK??