Just re reading your initial post, I suspect something was not configured correctly when the port was changed in the cabinet.
'How are the TV and sky box connected to the smarthub? i.e wired or wireless'
wireless - but not connected at the moment as using 4g mini hub
Logic would dictate that as nothing has changed at your end but something has changed elsewhere, it is that which has changed that has caused the problem.
Indeed, but in this case the issue started before the port change, therefore something else happened before the port change to cause the issue and so far it looks to be local
Without a verified working device, then it's impossible to rule it out, especially when you don't have a single wired connection.
It's always best to use a wired connection when diagnosing Internet issues.
Laptop and phone work fine connected to any other network including the 4g mini hub
Also, out and about my phone connects to bt WiFi hotspots no problem
Just out of curiosity, does your laptop/phone connect okay to your own BT WiFi hotspot?
That's interesting....
It connects to someone's BT WiFi but don't think it's my hub which is BT-Q6A2PN which is a full stronger signal