On the UK the VAT is calculated.
On the Ireland the VAT is added on the total but not on the VAT column
On the UK the VAT is calculated.
On the Ireland the VAT is added on the total but not on the VAT column
Create a Multi store environment. One for UK and another for Ireland.
Now modify your checkout page as per your requirement.
By default Magento does not have a configuration feature that allow different checkout themes based on country.