I'm currently in Denmark for 10 days and don't have any signal at all. I have tried restarting my phone. I have tried selecting the network manually. Roaming is on and was on prior to leaving the UK. I have a Google Nexus 6p and am unable to take the battery out of my phone. Anyone have any more suggestions?
I'm really sorry that you're having issues with your signal abroad. I want to get this all sorted for you. So I can do this, I've sent a PM your way. You can view this by clicking the purple envelope in the top right.