It is so sad to hear of Derek's passing. I had been googling another Derek when this notice popped up. Derek and I were in halls together at Exeter and he was such a kind, gentle man. I was always impressed by his imaginative guitar playing but less so by his (involuntary) facial contortions when soloing! I had lost touch with him by the mid-seventies but always remembered him fondly. One of the good guys.
Dave Johnson