LONDON - The estimated value of London’s October contemporary-art auctions is down 81 percent from 2008 as prices and lots on offer decline amid the financial crisis. Sales at Sotheby’s, Christie’s International and Phillips de Pury of “Part I” works during the week of the Frieze Art Fair are estimated to fetch at least 20.8 million pounds ($33.1 million), according to a total of auction-house figures calculated by Bloomberg. The equivalent sales last year had a low estimate of 107 million pounds.