Have the 900mbit full fibre to the property product.
Used to get really good speeds, especially in the evenings when kids are in bed. (Other people's, I don't have any).
Recently my speed tests to various places (Bath Uni, Oxford uni, local ISP hosting and so on) sits around 90Mbit and has absolutely peaked at about 114Mbit.
The test below is run over 10GBit ethernet on cat6a to a 5950x rig, so there is no issue with wireless or the machine not being powerful enough, I've seen plenty of maxed out 900mbit tests in the past.
I live alone, I'm running Unifi small business gear, I don't have anything else using the line. The speeds are WAY below the garaunteed 455Mbit promise so I'm wondering who I contact to get compensated.
At this point Im considering moving service alltogether, I don't pay for 900Mbit to get 10% and sit waiting for an hour for a game to download.
Step 1 will be to put the BT Smarthub back on. It'll be a good test to see what the speeds are like, and support won't do anything much unless you do. You'll need it connected for them to test the speed, and action the minimum promise.