Hi NickersG,
I’ve copied a reply from a previous post about a similar problem, might be worth a try.
For Android:
Select Apps from the Home Screen
Select Virgin SIM Toolkit Icon
Select Roaming
Select Mode
Select Manual
Select International-you are done, go back to Home Screen
To Switch back when in the UK:
Select Apps from Home screen
Select Virgin SIM Toolkit Icon
Select Roaming
Select Mode
Select Automatic and go back to Home Screen
Regards,
Dave