Thanks Alan, interesting ideas. Once set up, It sounds like there would be no user input. Normally on radiators, there is a lockshield valve and a manual valve (or TRV), for users to adjust. If, in this example, a user was able to turn off one or two radiators, this would surely have an effect on the balance of the system, so that possibly the reference room radiator, in the room with the thermostat, would experience a different flow from that which it was commissioned for, and an effect on any temperature difference, between eg bedrooms and lounge, which were designed for.

The OP, Peter, mentioned manifolds in their second post, so I assume they are wet UFH manifolds, one on each floor. 

As Andy said Approved Document L book 1 

"5.20 For heating systems in new dwellings, or when a heat generator such as a boiler is replaced in an existing dwelling, each room should be provided with thermostatic room controls. These should be capable of being used to separately adapt the heating output in each room served by the heating appliance. Where justified in accordance with paragraph 5.21, heating may be controlled for each heating zone rather than individual rooms."

But that doesn't preclude anyone from designing something different, as long as it is no worse than full compliance.

Edit; the building regs have hummed and ahhd about TRVs. They were once required, then when Boiler Plus came along they dropped the requirement, then last year they are back in, along with (one of the four) boiler Plus measures. 

I have UFH in my flat, I tend to leave the  thermostat at room temp all year round, but then I have cats who don't go out much ;)

OlympusMons said:

The OP, Peter, mentioned manifolds in their second post, so I assume they are wet UFH manifolds, one on each floor.

This is a big house, so possibly >1/floor.

IIRC, step-daughter's house has 8: 3 on the ground and first floors, and 2 on the top. The house is circa 200 m².

I can see the point in not heating the guest bedrooms, but if they are going to warm up due to heat below and to the side, the economy may be trivial.

BTW: IIRC, we used 4 core flex for the stats. (Hubby's choice, not mine.)

OlympusMons said:

The OP, Peter, mentioned manifolds in their second post, so I assume they are wet UFH manifolds, one on each floor.

This is a big house, so possibly >1/floor.

IIRC, step-daughter's house has 8: 3 on the ground and first floors, and 2 on the top. The house is circa 200 m².

I can see the point in not heating the guest bedrooms, but if they are going to warm up due to heat below and to the side, the economy may be trivial.

BTW: IIRC, we used 4 core flex for the stats. (Hubby's choice, not mine.)

Yes it’s a two storey 3000 sq ft house. I believe as others have said that it is a building control decision to have each room zoned which does make a lot more work for us. The design was done by a reputable heating company so have no problems with it, they are designing around what building control demand. As regards the original question of using flex to the stats, I think I will go with the flex to cut down on space aswell as this is what the design specifies!

Comfortable, but not huge!

14 stats still seems over the top, but I understand the reason why. The S-plan box must be a bit full!

I still have no problem with the flex - it seems an obvious solution.