Many thanks Scarlett
I have now got 17d, though I can't parse it and it doesn't fit with your hint for 23ac.
I thought 16 ac is an element, but couldn't find a seven letter element that fitted. I've checked in my book of the periodic table and now found one. Unfortunately, it means my answer to 9d God to blame ultimately in drama (foul one)? No, it was this bloke (5,8) must be wrong.
I now have ?I?G? M???D?N?
But I have just got 23ac
Back to the drawing board for 9d, 20ac and 5d, but bed first.
Thanks for your help.