Thermostats

As the weather starts to get colder (some possible lowland snow is forecast for the weekend!), I am discovering new issues with my house.  I don't have central heating - but I do have a digital thermostat that controls the main heaters downstairs.  This works like a dream.  However, I also have other heaters that are controlled by analogue thermostats (such as in the kitchen and main bedroom) - and these do NOT work like a dream.  They are supposed to be temperature-controlled, but they don't seem to be affected by changes in temperature - essentially they are either on or off depending on how much I turn the dial.  That is frustrating - particularly for the one in my bedroom.  I can either leave it on and wake up way too hot or leave it off and wake up freezing.  Not good.  I think I need to let my landlord know, in the hope that he can do something about it.