Hi, like a lot of Plusnet users I too am having issues with Wi-Fi dropping out on devices intermittently.
To set the scene; I live about 200m from any other property so there is no conflicting channels ( I have also tried all of them). I have also disabled the 5ghz Wi-Fi as nothing uses it. I have also done a factory reset. The signal is strong throughout the house and the Wi-Fi will just say no internet available.
If you log on to the router the log page says 'client disassociated'. It will eventually reconnect. It happens on all devices periodically.
Plugging in another Wi-Fi transmitter and connecting to that solves the problem for all devices connected to that one, but still not the hub one!