The song title could be a reference to 'Buckfast', colloquially "Buckie", a tonic wine infamous in Scotland for its potency and extremely high caffeine content. 'High' in this context would be a refrence to being intoxicated. [1]
Alternatively, the title may be a reference (like "The Beach At Repoint") to a real place in Scotland; Buckie is a small fishing town in the county of Moray. Scottish schools are like their American Counterparts known as High Schools (Secondary in England). It's a possiblity that they or friends/relatives may have attended this school influencing the title. Another nostalgia for their childhood? [2]. Coincidentally, perhaps, there is a café near Buckie High School called Sandisons.[3]