Green’s Dictionary of Slang

hot scone n.

[rhy. sl. = john n.1 ]

(Aus.) a police officer, a detective.

[Aus]Western Argus (Kalgoorlie, WA) 8 Dec. 32/1: A policeman the other night was to be seen with that rara avis — a light on a police bicycle. [...] Another ‘hot scone’ on Thursday afternoon rode up Maritana bridge and coasted down the other side with both hands off the handle bars.
[Aus]Baker Popular Dict. Aus. Sl.
[UK]Dodson & Saczek Dict. of Cockney Rhy. Sl.