<p>Barratt has seen a weaker than expected autumn selling season, with net private reservations per site per week dropping to 0.45 from 0.55 last year. However changes in housing mix have seen the firm increase its average selling price which will drive margin growth for the business this year.</p> <p>In an interim statement to the City issued today, group ceo Mark Clare said: "Our strategy continues to be value and quality focused in a market where customers are taking longer to commit to house purchases. Whilst the autumn selling season has been weaker than anticipated, our encouraging performance on price is expected to drive margin growth for the year."</p> <p>The firm, however, expects to open 120 new sites by June having opened 72 new sites in the past 20 weeks.</p>