By Marie-Louise Gumuchian LONDON (Reuters) – London designers are seeking to entice more demanding fashion followers with luxurious materials, rich embellishment and vivid colors, hopeful that the country's luxury industry will grow despite continuing global economic woes. London Fashion Week, effectively a trade show that sees hundreds of buyers, journalists and celebrities descend on the British capital, is expected to result in orders worth more than 100 million pounds ($159.35 million) during its September 13-17 run. …