The bottom line is that we are not supposed to be able to recieve U.K. television here. So to some degree or another anyway of recieving them is dodgy. If you have a decent broadband signal, probably the easiest way to recieve UK TV is with a set top box connected to your adsl there are a number of companies advertising this. There are also a couple of people offering Teleclub which is a small dish that recieves a relayed signal from a large dish somewhere near Femes I believe.
But they could be switched off if they are caught.
If it just for yourselfs you can also download torrents and watch most popular programmes the following day.
If it is for guests personally I would just say you have limited sky and go out and spend some money on the Island

Hope that helps
Ray