that is the best option. install the modem downstairs by the master socket, and run a cat5e upstairs to the router. The closer the modem is to the master socket, the better.
im slighty confused as i dont have a modem just a router
im using the black sky hub seems it works for fibre and adsl there is no way for me to have the router near the master socket there is no electrical sockets anywhere near it
will one of these not work http://www.ebay.co.uk/itm/3-Port-RJ45-CAT-5-5e-6-LAN-Ethernet-Splitter-Connector-Adapter-converter-PC-UK-/151267870073?pt=LH_DefaultDomain_3&hash=item2338448579
You can split it by using an unmanaged ethernet switchwww.amazon.co.uk/TP-LINK-TL-SG1005D-Gigabit-Unmanaged-Desktop/dp/B000N99BBCor run another cable