Robbo, you may need a very long phone extension wire, when I ordered multi room Sky stated that the box had to be permanently connected to the phone line, I thought oh ok, bought an extension lead and the box was acctivated, I then unplugged line and said sod them, within minutes I recieved a warning that if the line was not put back on multi room would be blocked.
Speaking to a Sky installer he told me that the line is checked daily to ensure that the box is being used at your home as people were getting multi room and putting the box at a different address, makes sense, get advice or you may be disapointed.