@IanD2firstly please forgive me as I'm a novice at this kind of stuff.
On your soloution where you turn off the 5Ghz band and rename something to the same SSID/Password as the BT Wholehome network, what is it that you rename? The 2.4Ghz SSID or the 5GHz one?
To me it sounds like you turn off the 5GHz band and rename that to the BT WH SSID/Pass?
I'll be very grateful if you could clarify this.
Yes, the Wholehome just broadcasts its normal wifi signal with both 5ghz and 2.4ghz are available. It's basically back to how it always was.
My 3 wifi plugs are all working brilliantly and connect to the wifi instantly.
I've also added them to my Google Home, so I can now ask google to turn the Christmas Tree lights on. I have timers set up on the plugs too.
I'm really impressed with them.
I gave up trying to connect my Sonoff 2.4Ghz inline switches to my new BT Smart Hub 2 after several fruitless hours!
Even with the 5Ghz switched off the switches still wouldn't connect to it.
So I have gone back to connecting them to an Ethernet-connected wi-fi access point running at 2.4Ghz located downstairs (the new hub is upstairs.)
This unit is actually an old BT Smart Hub 3 with it's DHCP switched off and set to a static IP Address of 192.168.1.252.
It is connected via a Cat 6 cable which I ran in when the house was being renovated.
It works fine with the Sonoff switches and even gives me Wi-Fi connectivity in the back garden.
Not a solution for most people, I know, but it works for me.
As someone said in another post on this thread, this shouldn't really be necessary and BT gets no plus points regarding this new hub from me, although, to be fair, it is a little faster than the hub it has replaced!
I hope this is of interest.