The new M&S chairman will face mounting challenges. Chief executive Roger Holmes has failed to impress. The company has tried a series of increasingly desperate strategies to turn the business around, from tinkering with its Lifestore concept to launching pelmet skirts for teenagers. But while it fiddles around the edges, service and enthusiasm inside the stores is dwindling, the food offering (once so often ahead of the pack) is struggling and the shops need a facelift.