I currently have a digistat3 digital controller for the gas central
heating, It does my flippen head in as I can never get to grips with
digital stuff (I have the same prob with the tv, controls for everything
and lets not talk mobile phones) I have to set mon-fri and 3 seperate
time zones and then others for Sat & Sun. Before this winter I would
like to get a simplified version.
Like one of those round dials that has 15 minute segments and you push
it in or out for on and off and then have a seperate thermostat for room
temperature.

Whats a likely cost for parts?
And is it an easy conversion. (I am not an electrician, ok with basics)

thanks