20 Down:
Old professors deserve interrupting that is on the rise. (7)
E _ E _ _ _ _
Looks like it might be "Elevate" as in 'on the rise' but I can't work round the rest of it.
Also 16 Down:
Previously popular leading man's touring time (8)
_ I _ H _ _ _ _
I'm getting 'hitherto' if the main definition is 'previously' but this is a bit of a guess.
Thanks.