I would take of smart and select channel manually
did you try factory reset?
I will try fixing the 2.4GHz channel.
Since 2nd July, the Hub has been factory reset twice and power cycled twice.
If this problem continues, I'll revert to my trusty OpenReach modem and Netgear Nighthawk router.
This should show Smart (Channel 1or another number) as your 5GHz does.
Try changing the channel in change settings
Thanks to everyone who replied to my original post.
I've used BT HH3, HH5 and now BT's Smart Hub 2 over the years, and they all have issues; sadly.
I'm not going to bother complaining to get the Smart Hub 2 swapped out, because I know that the issues are likely to be systemic.
I'm reverting to my trusty OpenReach modem and my Netgear Nighthawk X6 R8000 AC 3200 Router. No drops in traffic, no drops in signal, and excellent WiFi coverage.
The Smart Hub 2 can act as a doorstop.