Thank you both, drxx and malone.
I get it now, and I have to say that I am unimpressed with the whole puzzle. I felt the clues were too clever by half - I have never heard that meaning of 'skiver', and I'm not saying that I know everything, but I have been doing crosswords for over 50 years, and that clue seemed to be stretching itself too far, just because it could. And the endgame, now that I understand it, is plain limp. Now I'm off to find something else to be petulant about. Stamping my foot as I go.