Hello @StephenMck - Not a lot of info here, but I'll take a guess.
You can use your Smarty plan to roam in EU countries up to 12GB. You need to ensure that your device settings are correct (one-off change). If you need more data from your plan, you can buy a one day or three day EU Data Roaming pass.
All this is in the Price guide: https://cdn.smarty.co.uk/files/SMARTY-Price-Guide.pdf
