Thanks for your post @kgrindley, and a very warm welcome to you!
Sorry to hear of the issues with the mobile phone services
Has the SIM card only been used in one location or in multiple locations this morning?
How many bars of signal are you getting?
Do you have any error messages on the screen? - "No SIM" "Invalid SIM" for example
Can you confirm if text messages and data can be used?
It may be worth looking into these links for an idea of the status of the coverage in the local area;
-For SIM cards supported by EE
-For SIM cards supported by Vodafone
Kindest regards,
David_Bn