Temperature warning light

[ShiftZZ]

Just brought my van back after an mot and service, noticed the temperature warning light on and tge gauge well into the maximum, this is having only driven a mile.
Rang the garage, they can have a look at it on Thursday.
Its obviously not overheating, could it be a lose connection or a faulty sensor?

 

[Vipar]

Have they refilled the radiator or left the drain plug open?