Fewer sales and lower prices sent profits at London and south-east focused housebuilder Berkeley tumbling in the latest six months.Pre-tax profits came in at £52m for the six months ended 31 October, down 35% on the £79.6m in the same period last year. Sales fell to £290m from £453m.Berkeley said revenue fell due to a combination of a dip in transactions to 914 units from 968 units in the same period last year and a fell in average sales prices from £399,000 to £299,000, which has been predominantly caused by a change in mix with more affordable housing in the total.Again, there was no write-down on the value of its land holdings, with net cash at the half year rising to £345m."The sales market has continued to stabilise over the last six months and this has resulted in an increase in the value of underlying sales reservations compared to the same period last year, although this is a level some 40% below the historic average," Berkeley said.The firm adds it has committed to new land acquisitions of some 1,800 plots across 12 new sites. These sites are in London and the South East and include a prime site in Belgravia.