Handbrake warning light

Hi, I went to get a Towbar fitted today, a bit of a disaster really, not good service and a general cock up all around...more on this in another post..

Part of the issue arose when I tried to leave the premises.....the hand brake warning light would not go off!

It's a Broadway 16 plate built on a Peugeot boxer, apparently the fitter removed the driver side step cover to access the electrics..

Can anyone tell me if there is a switch on the handbrake that might need adjustment...
Is it possible that it was accidentally disturbed during the electrical installation?

Ray