Britain’s biggest housebuilder has delivered another set of record full year results, bucking the trend in a tough market. Persimmon revealed a 5.9% rise in pre-tax profits to £495.4 million for 2005. Average selling prices grew by 5% to £180,892 from £172,431. The company sold more than 7,000 units at about £1.25 billion, including an estimated £300 million contribution from …