I haven't checked the sources but my recollection is as Hootenany suggests. The band was supposed to be a collective but Ken was always a one-man band. He found Lonnie annoying. Chris said later everyone who worked with Lonnie found him annoying but still worked with him. Ken wanted to sack him: the others reminded him it was a cooperative and his was a sole vote so they left and replaced him. I saw Wally Fawkes at the Cartoon Museum some years ago: he was almost completely blind and had therefore stopped drawing. The Chris Barber website is a good source of "who's still alive" of the men who passed through the band.
RtS