Thought you'd all like to know :)
https://www.gov.uk/bank-holidays
In fact bunting appears there on any day when there's a Bank Holiday (except Good Friday) and has done for several years. On Christmas and New Year it's tinsel.
Whether or not the Bank Holiday page is 'buntable' is driven by info on this page (scroll to the bottom to see info for up to 2026) https://www.gov.uk/bank-holidays.json
Jo
(easily amused and inordinately fond of bunting)