last 3-help please-may have extra letter
lhs-20d group of birds at bay(unknown to) 6 C?N?E?
rhs 13a from time to time during short spells 2,8 I?/S?A???E?
14d sets out quiz prior to blast-off 6,4 ??U?T?/D?W? fourth down/
thanks
nb 1st letter14d=7th of 13a