Good Friday, Easter Monday, Christmas and Boxing Day in Scotland. Christmas only became a public holiday in 1958.
Interesting! There seem to be differences between English and Scottish holidays.
The main Christian denomination in Scotland is the Presbyterian Church, which was (technically still is) deeply Calvinist. As I understand it, one of the tenets of Calvinism is to keep the Sabbath holy, and just the Sabbath. Other Christian holidays that aren't tied to the Sabbath were viewed to be unbiblical (December 25th isn't mentioned in the Bible, after all) and therefore heretical.
Calvinists also saw celebrating Christmas to be a Catholic thing, too. The Anglican Church maintained more catholic elements in their worship, and returned to embracing their Catholic heritage pre-reformation in the mid 19th century (that's partially why so much of modern Christmas traditions have their origins in 19th century Britain).