Green’s Dictionary of Slang

to appreciate, to understand, to work out.

1935		Thieves Slang ms list from District Police Training Centre, Ryton-on-Dunsmore, Warwicks 11: Tipple: Find out.
1998		I. Welsh Filth 300: Eventually they tipple that you’re just a selfish cunt.
2001		I. Welsh Glue 46: We dinnae really git oan, ah tell this Alec gadge, but ah think eh tippled that.
2012		(con. 1980s) I. Welsh Skagboys 18: I’m shocked when ah tipple it’s Andy; his heid’s been stoved in, big time.
2018		I. Welsh Dead Man’s Trousers [39]: [A]h didnae git a sketch ay the cunt tae tipple how gone he was.