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** Oil & oil-related stocks the biggest drags on the UKmidcaps index with last year's worst performer Afren's 6.4 pct dip leading losses
** Afren, hit by slumping crude prices, a scandal that hasseen the departure of top executives and its exposure to WesternAfrica, lost a little under three-quarters of its value in 2014.
** The stock has given up about half the gains it had madefollowing a preliminary approach from Nigeria's Seplat PetroleumDevelopment Co
** Seplat has until Jan 19 to come back with a final offer
** Premier Oil, Wood Group and energyservices firm Hunting all off more than 4 pct
** Large-caps not escaping weakness: BP, off 3.1 pct,and Royal Dutch Shell, off 2.7 pct, the only 2 stockson the FTSE that have traded more than $100 mln by midday
** Oil prices, whose decline of more than 50 pct from peakshit in June rattled many energy producers, hit a fresh5-1/2-year low on Monday (RM: vikram.subhedar.thomsonreuters.com@reuters.net)
