Green’s Dictionary of Slang

custard and jelly n.

[rhy. sl. = telly n.1 ]

1. (Aus.) the stomach [= belly].

[Aus]Sun. Times (Perth) 5 Sept. 8: I got kinder sick of him and dotted him a dinnyhaser in the custard and jelly.

2. television.

[UK]S.T. Kendall Up the Frog.
[UK]J. Jones Rhy. Cockney Sl.
D. Shaw ‘Dead Beard’ at [Internet] Listen, if Lingers was anymore upfront about wanting you son and daughtered, he’d be running ads on the custard and jelly in prime time.