You can get a Sky box from where ever you like. The key item is the card. If your Sky boxes are not connected to a phone line, then Sky will not give you multiroom. They will however be happy to charge you for a second full-price subscription if you so wish!!
In your second room, you can plug in the box and you will be able to receive all of the free to air channels: all the BBC's, ITV's, C4's etc. You won't get the Irish stations not the likes of SkyOne, Living, Dave etc.