You can hear a tribute by Ritchie Blackmore and Rick Wakeman on the BBC via iplayer
starts at around 8 minutes 15 secs.
"I'd never heard an organist play that way before. Jon had a lot of flash to his playing, which I enjoyed. And, of course, he was such an amiable person too. There was no ego there. My favourite piece of his is on Hush; his organ solo on that is just unbelievable…"