Shares in van hire group Northgate are the worst performing in the FTSE 250 after it said it had overstated its debt reduction in its interim results last week. Net debts fell by £173m to £713m over the four months to August 31, not £205m to £681m as stated last week.Wellstream, which designs and manufactures equipment for the oil and gas industry, is another faller, after confirming that it has appointed Alasdair MacDonald as a director and acting chief executive officer while Gordon Chapman recovers from surgery.ITV is also out of favour, after JP Morgan downgraded the broadcaster to 'neutral' from 'overweight' in a review of European media stocks. The broker is worried about the advertising outlook. FTSE 250 - RisersMicro Focus International Plc (MCRO) 319.00p +5.80%Brit Insurance Holding (BRE) 199.60p +4.50%Dairy Crest Group (DCG) 377.50p +4.28%HSBC Infrastructure Company Ltd. (HICL) 115.70p +4.23%Caledonia Investments (CLDN) 1,632.00p +4.08%Halma (HLMA) 204.30p +3.18%PV Crystalox Solar (PVCS) 80.00p +2.56%Hiscox (HSX) 344.10p +2.53%Mitie Group (MTO) 255.30p +2.49%Close Brothers Group (CBG) 779.00p +2.37%FTSE 250 - FallersNorthgate (NTG) 25.43p -6.68%Arriva (ARI) 505.00p -5.25%Wellstream Holdings (WSM) 665.00p -5.00%Melrose (MRO) 181.40p -4.53%ITV (ITV) 46.23p -4.48%Great Portland Estates (GPOR) 268.50p -4.24%Lamprell (LAM) 176.00p -4.09%Restaurant Group (RTN) 201.40p -3.87%Peter Hambro Mining (POG) 886.50p -3.64%Enterprise Inns (ETI) 142.40p -3.59%