When I was a councillor, a resident came to me complaining of very poor broadband. It was so slow that to update his iPhone it took all night just to download the update. He lived on a small estate opposite where I lived, and it was a 'fill in' estate, in that there was an area of land that got filled in with about 30 houses. As it was an afterthought, there were no ADSL lines left, so the maximum speed was about 2 Mbps. I managed to get it upgraded as they were moving from copper to fibre, so it was a lot better. It was also done first in the town, as the council contributed to the cost, which then became a gateway to the town being upgraded quite early in the era of the Government giving funding to councils to get the upgrades moving. Needless to say, the estate were all very pleased to get the super fast connection.
So the moral of this tale is to contact your County Councillor to see if they can help fill in these holes in the network.