I am lookong to buy a zip and link superking from you, the idea being that I am less likely to disturb my partner because I sleep badly and get out of bed several times a night to go to the loo. Our current mattress is a miracoil 2000 superking and when one person moves the other is disturbed. Also two single mattresses will be easier for one person to turn than a great big Superking. Can you also tell me what an Extra King is? Our bed frame is an American one which is 7 ft x 7ft.