Area code creating apple ID

I'm trying to create a new apple ID. I live in the Netherlands but have a UK number. Every time I try to type in my number (with United Kingdom selected), it tells me "please choose an area code which matches the name of the country". My mobile phone doesn't have an area code. What do I type in this box? I've tried the first 2-3 digits of my phone number with and without +44 or 0044.