I agree re 15 bowergirl and actonhighstreet. I thought it was rather witty - it made me smile, anyways!
Re the abbreviation for 'not available' in 19d, I think it is more commonly associated with 'not applicable' - often given as an option on those now ubiquitous feedback forms. In what context would one use or see NA for not available? Other than that, a perfectly fair clue!
I biffed 20a as I knew the expression (having worked in TV for a number of years) and I was looking for a final word that rhymed with 11a, but I didn't fully get the wordplay until seeing Jono's comments. I could see Hamper in there, but that was it!
This felt a bit different to normal, though I'm not sure why. I did enjoy it though, so thanks Everyman.