And even Maplin sell the bits:
http://www.maplin.co.uk/Module.aspx?...=14&doy=search
CAT5 is just wire are the end of the day, and you only need wire for a telephone system. You should be able to feed the phone into one end of your cabling system, patch it through at the panel, then get the output at the appropriatye socket. Take the output from your master socket.