I am afraid that I have very little good news for you. I am pretty sure that you are on Cabinet 19 on the Marlow Exchange. That cabinet has already been upgraded to Fibre but is so far away from you that it does not matter. Fibre gets the signal to the cabinet but then it has to travel a long way on copper to get to your house.
We are on Cabinet 9 from the Littlewick Green exchange. Our cabinet has been approved for an upgrade that is being subsidized by the government. We are still pretty far from that cabinet but we should still be able to get speeds of around 9mbps...which coming from 3mbps is pretty good.
You have limited options. The easiest option, not the cheapest one though, is to go 4g.
I have one of these and am paying 30 quid a month for 25gb of data. This is not nearly enough for all of our needs as we use well over 100gb a month due to my work and our streaming/download of movies and the like. The connection is, however, really fast as our antenna is at the Bisham Roundabout. I am getting 20mbps right now though this does vary up and down as channels move around between cars and me!
The other option would be for your little collection of houses to get together and invest in a fibre run! Not terribly practical. Maybe get Bisham Abbey to setup a Wifi network for you from their connection? I think they have bought their own fibre to the premise. Again, not terribly practical.
Sorry that I don't have better news...........if you have any more questions let me know. If you do a phone call is probably the way to go.