4dn: you're right with mister. It can make a 10dn (mister in the sense of atomiser)
8dn: Your first I is wrong. Looks like you've gone wrong with 12ac
You've already got the 3rd part of the them - 4dn.
Thanks Peterm this is a big help.
I am now thinking TROIC for 8d
This leaves 12a as I?R? (2 words)?
Don't understand them/theme issue - which clue is this?
I've just noticed that your 27ac is also wrong. If you've got liege, the second and last letters are wrong. What I meant by "theme" was simply the subject of the preamble, ie 18dn, and the 3 words that have to be highlighted.