According to This Is London, there's a deal worth £140m, making it the most expensive apartment in the world. No details regarding the buyer, other than he or she is "international". And presumably not the owner this time. More here.
The rumour on this property a few years back was that one of the financiers of the development purchased the property at an inflated price to push up the £/sft as far as possible - couldn't possibly be true.