It's a bit odd to have a country's national holidays determined by when bank clerks are permitted to frolic. But then bank holidays well demonstrate the practical if incoherent evolution of most British institutions.
The Bank Holidays Act, 1871, was an attempt to reform the country's widespread, unofficial and time-honoured 'Saint Monday' days off by giving a commercial lead. It was not a deliberate replacement of God by Mammon; the new holidays followed the old festivals, with the exception of August, our first holiday not a holy day. Whatever, this one has always been the most raucous, disapprovingly familiar for drink-driven coach trips and unruly youth.
All Saints Day was ignored in 1871, leaving a late-year gap in St Andrew-less parts which busybodies have sought ever since to fill with Trafalgar Day, UK Day and such. Some of us, too, find it quite odd that in such crowded islands we all have a holiday at the same time.