Stock, suddenly no wifi.

(5.1.1) I was on wifi at home. I headed out and have been on mobile data for most of the day. I went for a coffee and my wifi won't work. Tried turning the phone off and airplane mode.

When I click Wifi it says it's on with no networks available. I click More settings and it says Turning Wifi on, but doesn't.

I'd rather not reset the phone, any ideas? Thanks.