As far as I'm aware, as you do not have a UK or EU passport and are not a citizen of the UK/EU, you should be going through the non-EU line in all countries, both when you leave and when you enter.
You are not an EU citizen, so you should always go through the non-EU Citizens line unless you are told otherwise.
Normally if you are travelling with your UK/EU partner, you will go through the same line together, whether that be the UK/EU or the Non-EU line, but it's always best to check which one you should go through.