Version: (using KDE Devel) Installed from: Compiled sources "United Kingdom" is listed in the holidays plugins in KOrganizer. The holiday dates actually are only for England and Wales, not the whole of the UK. Scotland and Northern Ireland, which are also part of the UK, each have their own holidays. This is an example the irritating habit that people have of using the terms UK and England as if they were equivalent. They are not! There are other parts of the UK which are not England.
You've posted the same bug twice. *** This bug has been marked as a duplicate of 65827 ***