In that case we would set the abbreviations to show both countries in the general case, but when there is a day in lieu, to show only the Republic of Ireland in the base case (ie. the Sunday) and only Northern Ireland in the duplicated date (the following Monday).
➢Variable Holiday Abbreviations work the exact same way as variable holiday names, except that you use the token <abr> to include the default holiday abbreviation (instead of using the token <hol> to include the default holiday name).
For more details on all the available variations, see the topic on variable holiday names.
Topic 182035, last updated on 01-Jul-2022