Having taken a line through a similar process - 9km from exchange and round 3km from cabinet to move from around 1Mbps to near 3Mbps on FTTC, I have seen how critical everything inside the house can be.
Get the modem or hub as close as possible to the master socket with a very short lead. If your router cannot go close by run a single Ethernet connection. If you can, just have a single phone connected, or if possible move to DECT with the base a little way away. Keep other electrical and electronic equipment such as TVs, fridges, &c away from the modem. And don't drape Christmas lights along the front of your house
By doing this, and locating the modem under a bed - we managed to squeeze another 200-300 kbps from the connection.
M H C
taurus excreta cerebrum vincit