Central heating questions?

HI, I am having a new A+ Rated Combi boiler fitted in a new Central heating system, and all the rads will have TRV's on them. 3 Questions :- 1) Is it still necessary to have thermostat as well ? 2) Is fitting foils behind the rads worth doing and 3) Any recommends for a straightforward 7 day electronic timer (With a battery backup for the date/time) I live in a medium sized 2 bed bungalow and only 1 living room