Hi. I hoping someone can assist in the setup of my 3 unit Deco P9 system.  I've linked the main unit to my virgin super hub and connected fine with everything working.  I then connected the second deco unit to a different area of the house (on the same circuit) and it connected fine.  Now trying to connect the 3rd unit to another location in the house (not on the same circuit) and it won't connect over WiFi. The app says it should be connected on the same network but I thought the whole point was to be able to connect the devices with either the electrical circuit or the WiFi. Can anyone point me in the right direction?