I think this
http://www.free-instruction-manuals.com ... 457824.pdf is instructions for old thermostat, there should have been a neutral connection to terminal 2, this worked a small heater in the thermostat that reduced the hysteresis (over shoot) however they would work without it, and often with a modulating boiler it was actually better without that neutral connection.
I will try to explain, with a modulating boiler instead of the boiler switching off/on it turns up and down to match demand, the main control is the TRV (thermostatic radiator valve) as it closes the by-pass valve opens sending hot water back to boiler which in turn reduces its output (modulates). Until it can't turn down any more, then it starts to cycle off/on.
However it has one big problem, in the summer it will continue to cycle, so the old wall thermostat is used in a cool room so in summer it will turn the boiler off and stop the cycling, and a large gap between off and on temperatures is good for that job.
As you say you want the temperature at different levels in each room through the day, to do that there are simple replacement heads for the TRV's like the eQ-3 at around £10 each so you can set different temperatures for each room to match time of day, no wiring involved, unscrew old wax head and replace with electronic head.
So bedrooms allowed to cool in the day, and living rooms cool at night, and you set the temperature in degrees C not silly *12345 which is really hard to work out.
Also they have some extra features, like window open detect, I use that in kitchen so when we unload shopping from car, the radiator stops heating the room while we are doing it.
Simple dial allows you to alter the temperature, but you can also set the eco and comfort temperatures as swap between two by pressing one button, plus a boost button.
Pay a little more and you can get bluetooth version so you can program with your phone, there is also the Terrier i30 which is very similar.
You can get £50 versions that connect to wifi and link to a wall thermostat, likely Honeywell EvoHome is the best, but I am talking about using cheap £10 models.
To use the thermostat your talking about you will need a neutral, but there are others which are battery powered, I have the Horstmann one in front of me at the moment, Flowmasta also make one, the latter three events per day. If you want wireless neutral free, the Nest e is the only one I know.
