Coolant Light

[Tom8]

Some time ago, the coolant light came on in our 2011 Disco 4. Dash temp gauge was fine, checked level in the tank and that was fine too.
Next time in the car same thing, off when I get in but comes on when accelerating. Seems when on hill or accelerating it sets it of.

Took to garage to have a look. New sensor fitted and cooling system checked no issues. Back in the car and light came on again. Two garages now had a look and neither have an answer.

Car is fine, even on long journeys no issue with temperature or coolant level.

Any idea what it could be as it is really annoying despite not causing issues?

Thanks