New EvoHome and HR92s with existing plumbed two zone CH

Hi,

Thanks to a failed oil boiler, I took the opportunity to replace the 20-year old heating controls with a system based around the new colour EvoHome. Our plumbed system consists of a single boiler that outputs to two CH zones (downstairs and upstairs) and HW.

Here's how it's configured (Phase 1) and what I want to achieve (Phase 2):

Phase 1 (completed)
Downstairs - Evohome controller thermostat bound with BDR91 controlling downstairs CH valve.
Upstairs - DT92E digital thermostat bound with BDR91 controlling upstairs CH valve.
Hot water tank - CS92 thermostat (attached to tank) bound with BDR91 controlling HW valve.

Phase 2 (to be done)
Upstairs - Replace DT92E digital thermostat with HR92 radiators TRV's

Is Phase 2 possible in a 2-zone plumbed CH configuration? Found the Evohome help line useless as they told me I had an unusual configuration and needed expert assistance. I find this hard to believe as the system to far has been simple to configure and design with help from a qualified electrician.

Any guidance appreciated. The system is working so well so far, I will be gutted if the 2nd phase won't work.