Thanks for the updated comments. Home Network diagram is now attached.
In the UK our providers are pretty much hampered by existing infrastructure and "ownership" BT (British Telecom) used to be pretty much the sole provider so the whole network was owned and managed by them. Slowly, and with the technology changes, new rules have come into place and the network is shared as well as new infrastructure being put in place. Mainly in the more populated areas (large towns/cities). If like me you are rural then regardless of provider you are stuck with using the BT infrastructure and the network repair and management organisation Open reach.
Whenever speed is questioned it always comes down to the distance you are from the exchange and at 1.5miles we apparently are doing exceptionally well to get anything like 7Mbs! Up until a couple of years ago when we had a really good engineer visit we could only periodically get to 1Mbs. He did some tweaks and we suddenly jumped top 7Mbs!! Fantastic.
Neighbours have moved off the BT system to a provision via Dish, more expensive to set up and as we are looking to move house we have not followed suit but will encourage the next owner to do so as the BT timeline for a better service to our location looks to be being managed by their unicorn department!