I've read through a lot of the chat about boilers and heating controls
that's been posted in the last few months, but haven't managed to find
an answer to my specific question, so here goes:

We are in the later stages of building an extension, which has involved
removing our tiny old Ideal combi boiler. It's going to be replaced with
a shiny Worcester Bosch Greenstar 42CDi combi (not negotiable, there is
a sizeable discount available to us on Bosch kit).

The heating system is a bunch of radiators, and wet UFH in the new
lounge, stairwell and kitchen.

This doesn't sound like it should be particularly complex or difficult
to control: but we need to make a choice between:

FR110 Programmable Room Thermostat 7716192066
FW100 Weather Compensation Controller 7716192067
DT10RF Digistat Optimiser 7716192053

Now these all have slightly different features:

* The RF one allows us to position the thermostat anywhere we like in
the house
* But the UHF rooms will have their own thermostat on the wall anyway
which controls a zone valve on the manifold
* The weather compensation controller claims to save energy by
monitoring the external temperature and measuring how quickly the house
normally heats up
* The FR and the FW claim to modulate the boiler to stop temperature
cycling.

What I'm inclined to do is to buy the FW100 and put the thermostat in
the master bedroom upstairs (which is the only room we always want to
heat which isn't on UFH), the rest of the radiators on TRVs.

But the question is, how weather compensation and intelligent boiler
controls can be connected to a UFH system which just calls for heat in
an on-off fashion? And does this destroy the efficiency?

We are still trying to choose between UFH systems from Polypipe and
Robbens Systems, to add a bit more confusion.