Green’s Dictionary of Slang

(UK society) very drunk on wine.

1982		Barr & York Sloane Ranger Hbk 158: chateaued adj. Sloshed on wine.
a.2003		D. Duffey ‘A Trumpet Player’ on Gondoliers Discussion section of Gilbert and Sullivan Archive 🌐 On the Friday he was noticeably – err, chateaued by the interval, and began playing the melody earlier than usual in the second act by joining in with Marco’s rendering of ‘Take a pair...’.
2014		Observer 25 May 🌐 The fictional members of the Riot Club have a simple aim: to get ‘chateaued’ on wine as quickly as possible and then to trash the place.