there was a helpful little exchange between ixion and syzygy, which helped with 19D (for 'having no zip', think energy... and an abstract noun rather than an adjective). Having the correct checking letter with 22A makes that clue more straightforward than it first appears.
I don't feel entirely confident about 21D either. What is the 'stocktaking' all about?
Pendragon...5ac has a homophonic element(recitation) that makes it work.
21d is a double defn(sort of)for place to keep stock and a place to display(avoiding round)