UK Bank Holidays

It seems like the only authoritative source on UK Bank Holidays is gov.uk e.g. it will include substitute days when Christmas Day is on a weekend.

You can use curl and jq to save the dates to csv:

curl 'https://www.gov.uk/bank-holidays.json' | jq -r  '["title","date"] , (.[].events[] | [.title,.date]) | @csv' > uk_bank_holidays.csv