Strugglling with last three:
23a "Mass disseminator of News Corporation, if our speaker joined (6); - - R - A -
20d "Dead queen 9, for example" (6); N - - - E -
16d "Terrible fist's second stroke" (6); - C - A - E
if these letter are correct I can only see SCRAPE but don't see how it parses
Any help much appreciated