I have a Sunvic TLX thermostat - this one, I believe:
http://www.uk-plumbing.com/sunvic-room-thermostat-tlx2259-p-1345.html?zenid=c9e346cf7cfee920947e2eba941f0dfc
The problem I'm having is that when it is set to 20 degrees and the hall, where it's located, is certainly colder than that (I...