Our Network Team have advised that the next step will be to arrange a BT Openreach engineer visit.
I'm just sending you a Private Message to confirm some details so we can arrange this visit.
We have figured out that the internet disconnection issues started to arise after applying the fibre speed boost, is there anyway to remove this to see if it fixes the problem before an engineer is required (still don't feel the issue is at home).
The fibre speed boost wouldn't cause any issues or disconnects as it only removes the 40mb cap and adds an 80mb cap instead.
If you have tested with a different router, cable and filter at the master socket, with all other equipment removed from the line then this will cover all the testing you can complete.