LONDON (Reuters) - The head of Marks & Spencer's clothing division may be on the verge of leaving the British retailer after less than two years in the job, Sky News reported.Jill McDonald could step down as the company's managing director for clothing, home and beauty as the division grapples with challenges to a recovery, Sky said. M&S declined to comment on the report.Shares in the retailer were down 0.7% at 206.7 pence at 0915 GMT. They are down 30% from a year ago.McDonald joined M&S in..