I've got the Turtle of the Osborne (that one and the John Taylor 'Pause and Think Again'). The 'Outback' by the way did come out on CD (FMP?) - not sure if it's still in print.
FMR did bootlegs of those Turtle sessions. They're interesting, though I'm not sure I'd say anything watershed occurs on them. Not for me, anyway.
The Howard Riley is pretty cool, though.
Is bootleg really the proper terminology here? I was always always under the impression that they at least got Osborne's permission... (and so I'm still, on some level, smarting at the sheer volume of bootlegs/sordid releases coming out of the UK/SA jazz reissue axis)
Well, Osborne being under longtime care for mental illness(es), the thought of him giving permission is kind of surprising. I was told that the Turtle reissues were unauthorized (by a reliable source), but I'd be pleased to hear something different and more reliable.