2d. Some nice nimble old Brits
4d. Paper envelopes not filled, perhaps
7d. Itching skin of guide introduced to listener
9a. Mostly unnecessary pointers (7)
12a. Cold weather beginning during test
20d. Flapper last seen wearing a hairpiece
21a. A gold-plated propeller on a boat
24a. Writer of plays and novel robs one (7)