Our tyre pressure warning light came on, we have tried to reset it but no joy, the tyre pressures are fine, we have even decreased them then re inflated them, any ideas?

Have you kept it pressed n for a few seconds?

Yes, repeatedly, it blinks once and then stays on

If you keep holding it after it has blinked, it should go off. I had the same problem yesterday. Tyre pressure was down, pumped tyres up help button in until it flashed then loosed go and it stayed on. So I did a little search on here and it said hold it down for a few seconds and it solved the problem. You should hear a bong one it's done.

Tried that no bong either

Also you can't reset it after it's come on until you've switched the ignition off and back on.

I try it every time I get in the car - eternal optimist

Try pressing and holding the reset button while you are moving.  It needs a couple of miles driving to recalibrate after tyre pressure changes.

Have you the same tyre brand and depth each side, it works from abs ?