1 down: Flier the setter's sent up in this vein? (6)
Letters: - I - R - B -
MIDRIB ('bird' and 'im') Fits, but does the IM indicate the setter is saying, I am'
Three to go.
Edited:
Could you tell me please, with a yes or no, whether the letters I have look correct?
The 7th letter of both 8-letter words is shared.
The 3rd letter of 22 down is the 5th letter of 24 across.
24 across: Precise in theatre (

S – R - - - - -
17 down: Ordinary novice supporting lady (6) L – R - - -
22 down: Brad and Angelina originally in love (4) N - - -
I’m fairly sure that last clue appeared a while back, but I’ve forgotten the answer.