22A Relatives of a pawnbroker (6)?
NIECES
I don't understand this one at all.
23A Did some evening work, perhaps (6)
IRONED
Again, I'm just not seeing this.
20D Scowl when let down (5)
LOWER
"Let down" = def, but I can't work out the function of scowl. I'm guessing it's something to do with GLOWER, but I can't see anything indicating the loss of the G.