We used to have a thermostat that you could move, that worked well for us combined with turning some radiators on and off.It was there when we turned up so no idea on costs etc.
Have you considered underfloor heating? Less energy, not mega difficult to install (you could probably do most of it, just need a sparky to wire it up)
However, there is a difference with "effectiveness". i.e. how the human occupant 'feels' in the room. single location 'hot' radiators can create draughts, whereas a lower temp over a larger area can feel more steady state if that makes sense.