Insurance firm Amlin was the top riser after it saw a 7.1% rise in gross written premiums for the 10 months ended 30 October, but warned full year results will be affected by ongoing market volatility and a rise in the number of claims made.Gross written premiums, the revenue expected to be generated over the period of a contract, rose from £1,916.6m in January to £2,051.9m by the end of October. Not far behind, WS Atkins, the engineering and design consultancy, saw half yearly profits before tax rise 11.3% compared to the same period of 2010.Total revenues at the company, which was responsible for designing much of the London 2012 Olympic site, were £842.9m, 26.9% up on the prior year. That revenue yielded profits before tax of £46.4m. The operating margin dropped from 7.3% last year, to 6.1% in 2011. It was good news all round for specialist healthcare group BTG, which saw a 140% rise in revenue and a 131% rise in gross profit as a result of high sales of its CroFab snake-bite treatment. Meanwhile, shares in FTSE 250 set-top box manufacturer Pace slumped over 21% on Thursday after the group confirmed that full-year profits will be well under previous estimates due to the problems arising from a plant closure in Thailand. Mothercare wasn't doing a whole lot better after it posted a first half loss compared to a profit a year earlier and while the International business goes from strength to strength, it expects the UK consumer environment to remain difficult through the key Christmas period.The Watford based babycare retailer also announced a structural and operational review of its planned UK business size and shape. Shares in embattled telecoms firm Cable & Wireless Worldwide continued to fall two days after it announced a big fall in profits. FTSE 250 - RisersAmlin (AML) 310.70p +6.04%Bwin.party Digital Entertainment (BPTY) 132.30p +5.00%Atkins (WS) (ATK) 561.00p +3.60%Home Retail Group (HOME) 75.00p +3.16%BTG (BGC) 296.00p +3.06%Allied Gold Mining (ALD) 164.80p +2.62%Taylor Wimpey (TW.) 39.95p +2.17%Ophir Energy (OPHR) 267.50p +1.94%Brewin Dolphin Holdings (BRW) 126.70p +1.93%DS Smith (SMDS) 199.10p +1.84%FTSE 250 - FallersPace (PIC) 47.03p -22.01%Mothercare (MTC) 137.00p -11.61%Ferrexpo (FXPO) 272.50p -9.20%Afren (AFR) 90.25p -5.99%Exillon Energy (EXI) 304.80p -5.93%Savills (SVS) 283.10p -5.85%Supergroup (SGP) 590.00p -5.30%Cable & Wireless Worldwide (CW.) 20.78p -5.07%Ocado Group (OCDO) 80.85p -4.99%Big Yellow Group (BYG) 244.00p -4.91%NR