Robin Menzel, a senior high-yield analyst covering industrials and utilities at Lehman Brothers in London, has left the firm. Menzel had been at Lehman for one and a half years. He could not be reached for comment. Stuart Prosser, a firm spokesman, declined to comment on his departure, other than noting that the firm is actively seeking a replacement.Luke Spajic, another high-yield analyst, has assumed Menzel's responsibilities for now, according to Lehman insiders. Spajic declined to comment.