One's played The Flower of Scotland, drinking in whisky (3,7)
I believe the answer is:
tin whistle
'one's played' is the definition.
I can't tell whether this defines the answer.
'flower of scotland drinking in whisky' is the wordplay.
'flower of scotland' becomes 'thistle' (I've seen this before).
'drinking' means one lot of letters goes inside another.
'whisky' becomes 'W' (phonetic alphabet: alpha, bravo, charlie etc.).
'in'+'w'='inw'
'thistle' going around 'inw' is 'TIN WHISTLE'.
'the' is the link.
Can you help me to learn more?
(Another definition for tin whistle that I've seen is " Cheap, six-holed metal flageolet".)