heated towel rail / radiator stopped working

[CatAndHisKit]

Was working absolutely fine, been used for half a day, daily.
When you turn it on, there is a little light that comes on (plastic button that turns, at the base of it).
Suddenly, when turned it on yesterday, the light came on and promptly gone off and it hasnt heated up).
I had looked online briefly, they mention the air and that it may help to bleed it - but the only screw that I can see is on one top corner and is very tight - not the usual small bolt that you can turn with a srewdriver, you need pliers (I haven't even got them - but not sure I should be unscrewing it as may cause more damage?). Ther is no pipe leading to it but just a short wire coming from the wall, and I though at first that it's a lirtle warm just at that lower corner but no, it's not today, so unlikely to be air, to my mind.
TIA for any advice!

It's an electric heater, no connected to pipes from the boiler, then.

Bleeding will be irrelevant.

Most likely some kind of electrical fault.

You can follow the flex back to the wall outlet or switch, there may be a replaceable fuse.

Are all other electrics in the house working normally?

Thanks, PJ. Yes other electrics are ok.
There is a small timer panel next to it near the flex. Strange thing is, when I turn it off, then on, the electronic clock starts working as the seconds show, but then stops after a few seconds. Jusr thinking if it was the fuse, it wouldn't even start?

I mean turn the timer on on the panel, not the turn switch on the rad itself.

you may have a high-resistance connection tht has burned away. Maybe it makes a bit of contact when cool, then stops as it warms. It might be in the wall connection or inside the heater.

The heater will have been factory assembled and the wall connection will have been done by a wo/man with a screwdriver so more likely the problem. Especially if the supply is spurred off another socket, which is common.

It's also possible (likely) that the timer has a small stand-by battery to keep the clock going. These often last a week or so.

Unless you are keen on electrical work I think you should ask a qualified electrician to take a look.

thanks, PJ - will have to call an electrician then...
I hope I don't need to turn off the main switch as I@m not sure which one it is (there is also an electric shower switch on the same wall next door to the shower room but don't which is which) while it's broken?