I have found this terribly arbitrary. If my assumptions are correct, most of the eight words relate to the theme, but in so many different ways. That doesn't matter too much as one has the redundant letters, except for 19A, where my word is a homophone for a letter, if it's correct. But it could also be a number. 20A is a bit of a guess, (a Kwik response?), but 7D could be anything. For the first part do I go with a squash player or a genuine type of the theme, and for the second is that a genuine example (of a tree?). Pah!