Across: 19. Ruby's defied over vacuous remark (4,3) d???, r??, 25. found less old scrap on the tip, by the way (9) e?t???i??
Down: 6. take back racket, briefly challenge people serving first (9) r???n?u??, 7. thanks organisation in letter on radio (5), 23. during the day, minimum of bag pipes (5) t???s
Thanks to all. I don't really see 'establish' but it seems to fit. 6 down seems to be a problem. If there was no 'u' in
it would that help? For 15 across I have 'noughts'. The clue is 'new leader at last hunted for ducks' Hence the 'u'.