Hi IanHatters,
Thanks for your post and welcome to the forums. It's great having you on board with us in the Community.
I'm sorry to hear that you are having an issue with texting from the USA currently. Your Mobile data doesn't need to be active for text messages to send.
So we can check our systems, and ensure the roaming is on correctly, I'll need to confirm some information with you. I have sent you a private message regarding this. Just click on the little plum envelope at the top right-hand side of the page to access your inbox.
Thanks,