Oooh! I noticed a problem this morning...
For once, I appear to be in the "small number of customers".
Mind you, I've noticed a pattern when there is a mobile outage: when it's O2, everyone complains O2 are terrible. When it's 3, everyone complains 3 are terrible. When it's EE, everyone complains EE are terrible. When Vodafone is out, everyone complains Vodafone is terrible.
I'm left to conclude we have no decent mobile phone service providers in the UK.