mc2xml does the merging for you. The command is -I uk.xml -o guide.xml
Maybe look at the tutorial post again. The only time I use notepad++ is to add one extra (very small) pull that I do. The reason for this is that the software only allows you to combine 2 files at one time and merge them. It might not even be an issue for those people using the Microsoft Legacy (Rovi) service.