Heating won't turn on

[purpleme12]

I have a combi boiler. Baxi.
The heating isn't coming on!
I turn it on at the thermostat, it does the flame symbol on there so it's doing what it should on there.
But on the boiler there's no light on the radiator bit and I'm guessing there's supposed to be a light when the heating's working
Has anyone had this happen before?
Does anyone have any experience with any of this?

Batteries.

Yes it was batteries.
Sounds so stupid but I really thought it wasn't because I'd already changed the batteries to the ones in my tele control and also because the thermostat was showing how it should do so I thought it couldn't be that.
Went to get new batteries just in case and it bloody worked!

Had this. It was the diverter valve. Quite common (and fortunately cheap to fix if you're out of warranty).

The thermostat