Last few but i'm stuck. Please help
12d Unfriendly competition which may involve the setting up of more magazines (4,4) -r-- -a-e
16d Finds fault with outdated school equipment (6) last letter S
20d Business undertaking not easily disturbed (4) ---m
18a They include a study of Greek races (8) -----i-s
21a He makes inferences from a show of hands (7) p-l----