It's a bulb gone at the back of the gauges. Sometimes they've been known to just come back on again, especially with a helpful thump.
To remove, drop the steering wheel down as low as you can, remove the 3 allen securing screws around the instrument hood and then two lower ones which you'll see when you drop down the wheel. Now there's also a phillips screw nicely hidden away behind the dash. To get access remove the fuse box cover then get yourself upside down with a torch and you 'll find it.
Then you can manoeuvre the gauge panel out far enough so you can remove the wiring connectors and then you can withdraw the gauge panel.