Best answer by Mohammed
It's pretty live and any recent charges you've incurred would update within the few minutes of it being incurred.
You'll need to turn OFF Roaming in your iD account as well as turning OFF Data Roaming in your phone settings.
To be safe, you can also turn ON Flight Mode and then just turn on WiFi.
The phone being in Flight Mode would prevent access to the network and any charges from being incurred.
It's also possible you have a £0.00 spend cap on the account which may have also prevented you incurring charges.
Hope this helps