Thank you both for a bove posts - I'm too old to worry about the distinction!

One more clue to go. It's one of those I ought to know,so will not give up just yet. I completed the remaining empty section yesterday evening, but would appreciate explanation of why answers are right, if they are that is.
24 across: Quintet sit rabbiting about incorporating singer? (7)
Letters: A - T - S - E
ARTISTE fits.
26 across: Get away with late arrival for hospital somewhere in London (4)
Letters: S - H -
So it has to be SOHO
ETA: Still getting nowhere with 27 across. Clue is:
British disarmed revolts, including one person holding up train (10)
Could you tell me please if the following letters are correct:
- R - D - S - A - D