I mailed SmartHome and it looks like the 3 gang 2 way only acts as remotes for the WiFi ones. So I will need to add 3 boxes beside the door to be able to control the lights.
Here’s their reply:
A WiFi switch can only be 1 way, this is the case for any WiFi switch on the market.
It is this reason we developed the ‘two way’ remote is basically turns the WiFi switch on or off by radio and is totally wireless.
So, I would suggest a 3 gang WiFi switch in your kitchen.
1 gang two way remote switch for hallway lights to control the 1 of the 3 gang WiFi.
1 gang two way remote switch for landing lights to control gang 2 of the 3 gang WiFi
Now the only issue you have is the 3 gang switch for the attic/bathroom and two way landing.
For this you would need a 2 gang WiFi switch for the attic and bathroom and then a separate 1 gang two way remote switch that will operate
Gang 2 of the 3 gang WiFi switch along with the intermediate land remote switch.
The two way remote switches have been designed to look exactly, and operate like, a WiFi switch.
They can be fitted to a standard back box, to replace an old switch, or thy can be flush fitted to a wall with screws or the self adhesive pads supplied, as they have no producing back.
that are powered by a 3.5v lithium battery which we have been advised will last up 3-5 years before replacement is needed and it is as simple as replacing the tv remote batteries.
Another point to consider is that any 1 gang of a WiFi switch can have up to 14 remote gangs paired to it.