Shares in Redrow rose 3.6% after the housebuilder reported record results for the fourth year in a row.Pre-tax profits for the year to 30 June jumped 26% to £315m at the FTSE 250 firm, with revenues up 20% at £1.66bn.Chief executive John Tutte called the results “exceptional” given “an uncertain political and economic backdrop as a result of Brexit” and an industry-wide skills shortage.The government’s Help to Buy scheme has been a big boost for housebuilders.However, the scheme – which aims to help first-time buyers – is due to end in 2021. Redrow’s chairman, Steve Morgan, told the BBC the company was taking to the government about an extension of the programme.Redrow was not the biggest riser in the FTSE 250 index. Shares in Aveva leapt by more than a quarter after it announced it had agreed a deal to merge with the software arm of French energy group Schneider Electric.Halfords shares rose 3.7% after the retailer said it had benefitted from more people opting for “staycations” this year – holidaying in the UK – given the weakness of the pound. Strong demand for car roof boxes and camping gear helped like-for-like sales at Halfords rise 3.5% in the 20 weeks to 18 August.After spending most of the morning in positive territory, the benchmark FTSE 100 index lost ground to stand 11.25 points lower at 7,400.22 by midday. Analysts said that investors remained cautious given the situation in North Korea.On the currency markets, the pound rose 0.3% against the dollar to $1.2967, and was also 0.3% higher against the euro at 1.0900 euros.