26a Returning elected for one term, brought about a large change in Africa? (10)
??A???G??? (not certain of the "G")
23a It's fatal to tick box without first rough pre-check(ignoring chapter) (8)
O???C??? (not certain of the "C")
I've pencilled in dodecagon for 16d - figure cook did best when serving up good leg - but it was only a guess and I don't see how it fits the clue
Thanks for any help/explanations