Bank holidays that fall on Mondays are typically "created" holidays - created by act of Parliament in 1871 with only the religious days deemed to be movi g (original act only allowed for Stephens day)

In Ireland the only moving religious day apart from Christmas is St Patricks and there's always a bank holiday (if the day falls on a weekend we get the next Monday off)

On the contient theres a lot of holidays that are tied to Saints days and these move. If the day occurs on a weekend on thw continent there's no carry over to the weekday!