Go for the King’s Head, perhaps, turning up drunk to drink (4,2)
I believe the answer is:
toss up
'go for the king's head perhaps turning' is the definition.
I can't judge whether this defines the answer.
'up drunk to drink' is the wordplay.
'up' says the letters should be written in reverse (in down clue: letters go upwards).
'drunk' becomes 'sot' (sot can mean a drunken person).
'to drink' becomes 'sup' (to sup is to drink).
'sot' written backwards gives 'tos'.
'tos'+'sup'='TOSS-UP'
Can you help me to learn more?
(Other definitions for toss up that I've seen before include "close thing" , "unpredictable result" , "It's an even chance" , "Spin a coin - prepare food quickly" , "It's as likely as not" .)