Dee left the group in 1969 for a short-lived solo career. They got back together in the 1990s, and had several concerts scheduled at the time of his death. Dee played his last gig in Germany in September 2008.
In the 1970s, he was a founding member of the Nordoff-Robbins Music Therapy charity. He was an active fund-raiser and publicist for the organization for more than 30 years.