African oil company Afren plunged as it defaulted on an interest payment while it negotiates a restructuring with lenders that could dilute the interests of shareholders.Aerospace and defence manufacturer Cobham was damaged by a big fall in pre-tax profit for 2014, despite higher revenue. The company's annual results were held back by restructuring and acquisition costs, as well as the strength of sterling.Miners Lonmin and Kaz Minerals were also both trading lower in a sector-wide dip.British auto and parts dealer Halfords was among the risers on speculation it could appoint retail businessman John Browett as its new chief executive after he left fashion retailer Monsoon last month. Browett, who has held executive management positions at leading retailers, is strong choice and his appointment may please investors, analysts say.Spirax-Sarco Engineering was boosted by strong underlying profits, which were up 12%, with 50 basis points of operating margin progress. Chief executive Nick Anderson said: "We can continue to outperform our markets and deliver further improvements in our business."Shares in Betfair surged after the online gaming group upgraded its guidance for full-year profits after a strong third quarter. RisersBetfair Group (BET) 2,094.00p +17.25%Spirax-Sarco Engineering (SPX) 3,447.00p +11.92%Pace (PIC) 380.30p +5.76%Essentra (ESNT) 1,039.00p +5.38%Greggs (GRG) 1,013.00p +5.19%Moneysupermarket.com Group (MONY) 272.30p +5.14%Morgan Advanced Materials (MGAM) 338.50p +4.77%Rentokil Initial (RTO) 139.50p +4.57%AO World (AO.) 185.80p +4.09%Halfords Group (HFD) 453.30p +3.97%FallersAfren (AFR) 5.85p -11.36%Allied Minds (ALM) 579.50p -7.06%Kaz Minerals (KAZ) 232.30p -3.61%Lonmin (LMI) 137.00p -3.59%Cobham (COB) 322.70p -3.09%Jimmy Choo (CHOO) 170.50p -2.46%Brown (N.) Group (BWNG) 426.30p -2.36%Domino Printing Sciences (DNO) 732.00p -2.01%Restaurant Group (RTN) 716.50p -1.98%Aveva Group (AVV) 1,501.00p -1.83%
