12a) A Mere 6 (6 is idiom) managed to store electronic reminder (4-7)
??D? M?M?I?E
14a) An awful lot like a cakewalk maybe? (9) ??U???N?E
14d) This business arose controversially on Cape complex (9)
20d) Ease top off many times. (5) O????
All help really appreciated.