My temperature gauge in the dashboard is showing strange behaviour. The dial is moving into the red at random times...independent on whether I'm stuck in traffic or on the motorway. Temp seems to increase quickly and then decrease .....it's not as gradual as I would have imagined.

Also, my heating system does not seem to be working very well. We're going through a cold spell at the moment weather wise but depsite my daily journey of approx 20 miles I'm still cold on arrival at my destination.

Any suggestions?
Thanks