I was thinking of "AURA" (Zeus turned her into a fountain) but apart from being somewhat of a stretch it would muck up your 'E'.

"SCRIVENER"? Anagram of 'service' and 'RN' - the latter being the 'senior service' and a type of cigarette produced by Players. Convoluted? Backhander/Bribe/Broker/Scrivener ??? Dunno. Anyway, again, it'll muck up your 'E' in this one too. I shall retire.

Why am I confusing myself and attacking clues about which I know sweet bugger all? 23 Down could be "LEDA" ... If I recall correctly Zeus diguised himself as a swan to seduce her - which would make her a pen?

That would blow 'Scrivener' out of the water which, given the 'E' conflict sounds reasonable.

All correct, I think. NORA came to me in the night, and I'd actually considered LEDA but not added it up right and gone off on some other tangent. I would never have had any hope of getting SHAMATEUR, a word I don't think I've ever encountered before. It doesn't appear in my (somewhat old) Collins English Dictionary, for example, although it does turn out to be the only result of egrep ^s.a.a.e.r$ /usr/share/dict/words.

Anyway, thank you: not only insanity avoided, but a new word learned as well. I shall be forever trying to find excuses to use it in conversation :)