UK high street retailer Marks & Spencer has admitted that the sale of its US supermarket chain Kings , as part of its restructuring and refocusing on its core UK business, is taking longer than it had hoped. The retailer's CEO Luc Vandevelde hinted around two weeks ago that market watchers could expect a deal to be signed this week. But none has yet materialised and a spokesman for the chain conceded that a sale could take several more weeks.