(ShareCast News) - London's mid-cap index was up 0.9% to 17,037.26 at 1325 BST, tracking a more buoyant tone overall following a positive session in the US and as the closure of Chinese markets gave investors a chance to catch their breath.Motor retail and aftersales service company Lookers surged after announcing the acquisition of Addison Motors Limited, trading as Benfield Motor Group, for £87.5m in cash. The deal, which is expected to be immediately earnings-enhancing, is being funded using new banking facilities made available to Lookers by Bank of Ireland, Barclays Bank, HSBC Bank, Lloyds Bank, Royal Bank of Scotland and Yorkshire Bank.Hedge fund Man Group rallied after it emerged that the company will not be facing a probe on its China operations. The stock fell sharply on Tuesday following a report that the chairwoman of its China unit, Li Yifei, had been taken into custody by Chinese authorities to assist with a police probe into market volatility.TalkTalk pushed higher after Exane BNP Paribas upgraded the stock to 'neutral' from 'underperform' and lifted its price target to 260p from 210p to reflect the potential for improved news flow through the second quarter after the recent sharp de-rating.On the downside, shares in Go-Ahead Group slumped after the company posted a 13.7% drop in pre-tax profit on the back of exceptional costs and said it will take longer to hit targets for its bus division. Pre-tax profit for the year ended 27 June fell to £78.7m from 91.2m last year as the group suffered £8.8m in exceptional costs. However, on an underlying basis, pre-tax profit rose £96.6m from £84.9m. Meanwhile, revenue rose 19% to £3.22bn thanks to a strong performance in the company's rail business.Among the fallers, Amlin, esure Group, Micro Focus International and National Express all went ex-dividend on Thursday.RisersLookers (LOOK) 178.50p +7.99%Man Group (EMG) 159.20p +6.49%Indivior (INDV) 229.70p +5.76%Thomas Cook Group (TCG) 107.90p +4.05%Berendsen (BRSN) 1,025.00p +4.01%TalkTalk Telecom Group (TALK) 298.90p +3.10%Barr (A.G.) (BAG) 568.00p +2.99%Kaz Minerals (KAZ) 160.20p +2.89%Rotork (ROR) 208.00p +2.82%Provident Financial (PFG) 2,956.00p +2.82% FallersGo-Ahead Group (GOG) 2,354.00p -7.18%Lonmin (LMI) 29.20p -6.56%Michael Page International (MPI) 482.00p -3.15%Micro Focus International (MCRO) 1,234.00p -2.68%esure Group (ESUR) 233.30p -2.51%National Express Group (NEX) 292.60p -2.50%Zoopla Property Group (WI) (ZPLA) 236.90p -2.43%Evraz (EVR) 67.00p -1.69%Petra Diamonds Ltd.(DI) (PDL) 119.10p -1.65%Amlin (AML) 498.00p -1.39%