Hostelworld as a Northern Irish person is kind of funny..
I've noticed this over the years using hostelworld although I've just noticed one more issue that made me laugh in slight frustration.
When asked nationality as a Northern Irish person, I would typically look for Ireland, United Kingdom or British depending on what passport I'm using (people from NI have dual citizenship, so therefore 2 passports).
Anyway, the one and only website that I know of that has 'Northern Irish' on the drop down menu is hostelworld. The first time I booked, i looked for all of the aforementioned, even for Great Britain, which would be technically wrong, but a lot of websites don't know the difference between UK, GB, NI, Ireland, British Isles and so on. It took me about 20 minutes to actually even think to look for Northern Ireland.
So today I go to make a booking for a hostel tomorrow night and did the above. On the next screen, it asked for details such as email and phone number. The dropdown menu for +44 country code wasn't under UK, GB or British Isles, this time I had to search for and click on England to get +44 to pop up.
This leads me onto the payment screen where I had to type in my home address, and in order for it to greenbox, I had to select United Kingdom for my country.
So in one booking, I have 3 nationalities, Northern Irish, British and English. Mental. It should be all uniform instead of keeping us NI lads and ladies guessing our nationality.
And bonus info for the uninitiated - it is a bit complicated.
GB - England, Scotland and Wales. The big island.
UK - Great Britain and Northern Ireland.
British Isles - UK + Republic of Ireland and all the islands.