Want to use Tado but its so un clear what will work

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Ive opened a can of worms by researching the heating system for our refurbishment.

We are having a central heating system installed. 

The proposed boiler is a Vaillant ecoFIT pure (think 618 but not definite). 

The heating will have 3 underfloor heating circuits for two zones. Builder intends two Honeywell t6360b room stats in each zone, with the third zone being the rest of the house radiators (5 of them); (controlled by a Nest). 

The non TVR lead radiator is a towel rail in the bath room. 

I want a smart heating system but keen to ensure the system is modulating with weather compensation. 

I've done some research and see that the boilers modulation ratio is basic at a max of 1:5. This could be improved in sure, seems 1:10 is what should be aimed for.

As we are in the Apple ecosystem so I was pretty keen on Tado for homekit compatibility but am disappointed to see they have removed modulation through BUS control in their new starter kits (v3+) in favour of a cycling system in the UK. In addition you need to have the newer bridge to make it Homekit compatible. So using Tado would mean gathering old and overseas components. 

Its also ambiguous if the Vaillant is compatible as it states on Tado - VRC-410/410s or VRC-420/420s, multiMATIC 700 boiler controller is not compatible. However Vaillant state the boilers are fitted with - Boiler Plus compliant with time and temperature controls – "Install with VRT 15, timeSWITCH 160 and VR 66 wiring centre for the easiest way to meet Boiler Plus". The VR 66 doesnt support eBus so doesn't support modulation......


Can I make Tado work? If yes would the system be limited to cycling or is modulation possible? I can still change the boiler but would prefer not to if possible.