Wiring for UFH & radiators with Nest thermostat

[Azz00]

Hi everyone,
My plumber is coming over on Tuesday to connect up my UFH heating in the extension. This plumber has done work for my family for years and is a great plumber. However, he has never done any UFH work and I just want to make sure I know whats happening.
The existing scenario is that we have a combi boiler and rads all over the house that are connected to a nest thermostat.
The UFH manifold is installed below the boiler and is ready to be connected up.
What I want to happen is to be able to control the radiators separately to the UFH.
So the radiators will still be controlled from the NEST thermostat and the UFH controlled from a dial thermostat that came with the kit.
I have found the image below. But it makes use of a programmer. Is it possible to do away with the programmer? As far as im concerned, if I want the rads on I will use NEST. And then I will just keep the UFH at a constant temperature from the dial thermostat?
Thanks in advance!

 

[Lower]

You could do that, but that means your underfloor heating will always be on, albeit controlled by the thermostat.