Hi Kayakamina
I hadn't missed the point. I said I understood Lie-inKing's logic. I wasn't in fact disputing that 'fanny' was the answer.
I was simply keen to know why the wordplay couldn't be applied in the way I was suggesting. ie that the answer related to 'female' (rather than nothing) and the 'nay', inspiring 'n' and'n' related to the components of the clue.