I have one particular fond memory Of Diz. He was appearing at Cambridge Folk Festival with Stephane Grapelli and Birelli Lagrene in the late 70s or so. Pure jazz magic. He then spent the entire night wandering round the campsite sitting in with the impromptu jams, just playing along, not doing the big star thing. I still wonder how his white shirt and trousers didn't show any trace of mud/grass/beer stains!