Their FB page says:
We’re EE – the UK’s biggest and fastest overall network, offering 4G in over 100 towns and cities, as well as Fibre Broadband.
This is the coverage map for where I live….
… pretty crap really… my phone “Should” work outside most of the time.
Interesting contract – I promise to pay them money every month and they provide a service that “should” allow me to make calls.