Thank you waigo.
The unit we selected is 19.5kW and 7 zones. Bedrooms and living areas are separated by these zones. BASIX site just talks about just zoning. What I we want to know is, should we have to do more than zoning for this?
No Basix just says you need to have at least 2 zones. If you have 7 zones it will be fine as that is better than 2 as you can only run areas you are using which is better for energy consumption generally.
This answer could solve a 6 weeks debate with EBH and us. Thank you very much