By Laura McGuire House builder Crest Nicholson said operating profit cratered in the first half of the year as the firm continues to be bruised by challenges in the property sector. The board of the FTSE 250 firm said the figure slid 71.9 per cent on last year to £6.2m, while revenue over the six months to April was down 8.9 per cent to £257m. Crest Nicholson said it was still feeling the pinch from a tough market, with volatile mortgage rates and low consumer confidence having eaten into property builders’ bottom line in the last 18 months. Over the period, Crest completed the build of 788 ne…