The perfect solution might be Honeywell's Hometronic Kit

http://europe.hbc.honeywell.com/hometronic/default.htm

1) Its Radio based so won't involve chasing walls out and cables everywhere

2) Has various Daily, weekly, vacation and personal setpoints can be set for each room.

3) Fully expandable so if you decide you want to automate some Lights, Blinds, Appliances at a later date you can add modules.

4) Can be operated via a phone, so you could put your heating on as you drive home.

5) A web interface has also just been developed

6) Digital input modules are also available to interface into other kit for example alarm system. When the alarm is set your heating would go to set back.

Its quite expensive though costing around 1000 for a basic system

I can send some prices and some example diagrams / schematics

I can supply the equipment and schematics for DIY install nothing to complicated just depends on the system

Commissioning can be arranged if required

if your interested drop me a line.

Jason