Moving from 3 Nest zones to Atari

Just need some advice on whether my set up will work and exactly which kits to buy in the UK

I currently have 3 Nests, controlling 3 zones in my house and hot water (Upstairs, Downstairs, Kitchen wet UFH)

Each nest controls a 2 port valve and ‘call to heat’ to the boiler (standard call to heat, not opentherm)

I want to replace each Nest Zone controller with a Tado thermostat, and I also want to add smart radiator valves to some (not all radiators). Is this possible. I couldn’t find any wiring diagrams on the Tado website that showed this.

If my (for example) downstairs thermostat is satisfied, but one of the radiators in a room wants heat, will it call for heat via the downstairs stat? Can Tado support multiple smart trvs in the same room?

Sorry for lots of questions