Good fun I thought.
Chris, the specific definition in 6d is in Chambers, though I didn’t know it.
Ffawkes I can see how you were seduced by ORION, that’s quite funny. Fortunately I had some crossers in place before I got to that one.
Well, I've ground to a halt on 6a, everything else completed so I have 2 crossers which I think are OK, but I can only really think of solutions which match one, but not both words of the clue!