Welcome to this user forum.
The two hour limit is part of the BT WiFi T&Cs. Fair usage policy.
You need to use your normal home hub wireles SSID, not the BT Wifi one, then you will not get disconnected.
How will changing providers help?
If you have exceeded your monthly minutes, then that is why the disconnection policy is affecting you. As far as I am aware, that policy has been in place for a long time.
You could buy extra time with vouchers, and use the public access page.