Car- and bike-parts retailer Halfords saw its shares rocket after delivering an impressive first half. The group posted profit before tax in the first six months of the year rose 6.4% to £44.6m, well ahead of the £38.9m forecast by analysts. Adding to the gains, Investec reiterated its 'buy' rating for the group and upgraded its forecasts. Cable & Wireless was also higher, despite a fall in half-year profits. However, the group said earnings before interest, tax, depreciation and amortisation (EBITDA) climbed 3% to $298m as Panama returned to growth and the Caribbean achieved a 6% reduction in operating costs. The company also recognised a gain of $1bn following the completed disposals of the Islands, excluding the Seychelles, and Macau businesses. Engineering group Renishaw climbed on the news it has received and accepted an offer from Autodesk, the US multinational software corporation, for the entire issued share capital of Delcam, a firm in which Renishaw holds 1.54m shares. The sale would equate to a total consideration of £32m. Meanwhile, Dairy Crest dropped after it revealed a mixed set of half-year results as progress at its four key brands was offset by persistent difficulties its Spreads division. Adjusted pre-tax profit climbed 18% to £21.9m while revenues during the period fell 2% to £672.2m. Group operating profit dropped 6% to £27.3m after a weaker performance in spreads.Satellite communications group Inmarsat declined after it warned that 2014 profits will not only be squeezed by the well-flagged delays to its next-generation satellite, but also by extra costs from other projects and lower spending from the US government. FTSE 250 - RisersHalfords Group (HFD) 479.00p +14.40%Centamin (DI) (CEY) 51.45p +6.52%Grainger (GRI) 208.50p +5.84%Beazley (BEZ) 241.00p +5.66%Cable & Wireless Communications (CWC) 48.30p +3.87%Imagination Technologies Group (IMG) 262.20p +3.39%Wetherspoon (J.D.) (JDW) 741.50p +2.99%Xaar (XAR) 850.00p +2.66%Polymetal International (POLY) 591.00p +2.34%Renishaw (RSW) 1,717.00p +2.32%FTSE 250 - FallersDairy Crest Group (DCG) 517.50p -3.99%Inmarsat (ISAT) 689.50p -3.43%Hunting (HTG) 878.00p -3.20%Telecity Group (TCY) 681.00p -2.78%Ashmore Group (ASHM) 386.00p -2.33%Balfour Beatty (BBY) 276.30p -2.02%Fidelity China Special Situations (FCSS) 101.20p -1.94%Partnership Assurance Group (PA.) 404.00p -1.94%Domino Printing Sciences (DNO) 670.50p -1.69%Smith (DS) (SMDS) 296.90p -1.62%NR