Richard knew Michael Hoppe for many years and worked as co-producer with him on several albums, including his Unforgettable Heart.
Michael Hoppe's site

Tim was featured on Richard's album Treasures of the Saints.
Tim Wheater's site

Another musical collaborator is Steve Roach.
Steve Roach's site

A tribute to Richard was recently made on the Hearts of Space radio program, and the show can be listened to on their website (after buying a short-term membership). The program is PGM 794 called "Across the View"
Hearts of Space site