Marshall is good on that Graham Collier "Down Another Road" LP (Fontana, reissued on CD)... and yes, he does get a track pretty much to himself. Have you checked out Collier's music yet, AK? The first three slay me, the others mildly jab.
If you're not hip on Elton Dean, then I would avoid "Hoppertunity Box" and "Monster Band" like the plague, as well as much Soft Machine from the early 70s. But then, avoiding that stuff takes a big chunk out of one's exposure to the British jazz/rock cross-pollination, which is pretty endemic to all the stuff you're wanting to hear.