As part of the shipping method setup you can now choose to 'Despatch on Bank Holiday'. This is particular useful when a warehouse works on a bank holiday Friday for Saturday or Sunday delivery options. It also ensures that the estimated delivery dates are taken into account.
Where do I find it?
Within the shipping method setup /edit page, with the despatch days.
By default this feature is set to 'No', if you do activate it remember it affects all bank holiday dates for England & Wales.