Very sad. 'Solid Air' is one of my all time fave mellow records -- was introduced to his stuff by a room mate from Glasgow in college. "I'd rather be the Devil" became a kind of anthem for a while...
Saw J M live twice in the 80's, once with Max Middleton on keys (promoting the Grace and Danger album, I think). Absolutely magical performance. He always seemed to have a killer fretless player with him too. John Giblin played on the album I think, and a young whiz kid filled in capably at the live gig.
I remember reading a quote from him in Mojo saying that his early inspiration was a far out echoey jazz album by sax great Pharoah Saunders (who I also saw live once in LA). It inspired him to start messing around with echo pedals, and a new psychedelic folk sound was born!
Very sad to see him gone. But I think he left behind so much enduring and timeless music, his name will be known for a long time yet.