Cannot parse these last 2 clues:
5d Scold desperate man ousting Rex's son (8)
Looks like Harridan, is it something to do with Rex Harrison?
12d Vacillate disheartening a digger of trenches (6)
Dither fits, which explains the first part, but the "a digger" rather than just "digger" I find very confusing.
All help gratefully received, with thanks in advance