Guardian Prize

[kiddlytivey2]

8d. Place snail owns spiralling, as a working rule (10, 3) -A-K-N-O--, -A- I only could get mackintosh hat (or cap) which makes no sense to me.
4a. Start high, then go down (6) -F-S-T I have offset but can't parse it.
21a. Interrupting date, parent wearing nothing returns in checks (8) I have examines (for checks) but can't parse.
Bit lazy to ask all this in one post - sorry. Help appreciated

[Lie-in King]

8d Parkinson's Law - 'park' (place) + anag 'snail owns'
4a Offset (start) - 'off' (high; rotten) + 'set' (go down)
21a Examines - 'ma' (parent, wearing) 'nix' (nothing) (both in) 'see' (date) (all back)

[kiddlytivey2]

I knew I could rely on you as usual, Lie-in. Many thanks