gas central heating/thermostat /valves question.

[jeannamacs]

I would like to know if anyone could tell me what they think causes this to happen. -
I live in a 3 bed semi with radiators in all rooms. we have a thermostat in the hall controlling the heat downstairs. Upstairs the radiators have what i think are called TRV's where i can adjust the temp. I have a radiator in the conservatory downstairs which also has a TRV.
- I have noticed that sometimes the hall thermostat is on high and the rooms/hall downstairs can be quite cold, so i have to raise the thermostat to 30 degrees. I hope this makes sense,but i would like to know if this is caused by the conservatory radiator. Does anyone think that the cold temperature in the conservatory may be affecting how the temperature raises in the whole downstairs of the house?
May sound ridiculous, but i cant think of any other explanation.