Are you interested in the early sounds of Canterbury? There are several records with bands later turning into Soft Machine (among others). Brian Hopper collected 4 CDs with Canterbury Sounds, and there are records by both Wilde Flowers and Daevid Allen Trio, if you really need everything. The sound quality is not up to date, but there are lots of interesting tracks for completists. Some avant garde jazz, some rock and roll and even Jimi Hendrix on bass.