12ac My word is a culmination of reliability (1 3 ) I/ -A-
17ac Question a line one with a collection of properties (6) ---L--
21ac Range prepared endlessly good cakes given recipe ( 3 6 ) --- / -O-K-R Could it be aga cooker ?
18dn Sea with girl swimming ? Capital (7) ----E-L
19dn French are participating in journey and meaning to stay (6) R---D-