If anyone has this problem then if your skyId does work for your new account just ignore the message to unlink an old inactive account. I've rang Sky (on 03337591018) three times and even they couldn't solve it! Once you've been through the steps to unlink old account and link new account then the message to unlink doesn't show at their end. They were brilliant in listening to me but couldn't solve it. So I would say it's nothing to do with particular households or individual customers but something for the Web maintenance team to look into.
Unlink an inactive old account and link your new account loop
