Oh of course Barry! Thanks for that! Although, to be picky, surely people who have this hobby don't just go for the British ones?! That would seem to be quite limiting.
I don't really understand 10a either. Just can't make it work. If you wrote down the answer as it would sound if you said it with the answer (sorry, I know that's obscure but I'm trying not to give it away!) then P(ower) wouldn't come forth, it would come fifth.
And I agree about 5d - I don't think I've ever seen a clue like that before and I have to admit I only parsed it after biffing the answer, but it works brilliantly. So that is my joint COD with 15. I also, for once, enjoyed the Spoonerism too!