Yes, I read that the bit where she came back was filmed live and on location so that no one would see her at the studios beforehand. Fabulous when so much in the soaps is available as a spoiler weeks in advance.
It has to be something like witness protection, I can't think of any other reason why her sons would be told that she was dead. It'll be interesting to see Ian's reaction! Especially when he sees that his 'dead' mother looks younger than he does now
60? I remember watching it when it very first started and I seem to remember that Ian, Sharon and Michelle were around my age, so would be mid 40s now, so are we to believe that Kath's in her mid 60s?
BTW loved how the finding of Nick's body echoed the first episode