Persimmon completed 14,572 homes in 2015, 8% up on the year before, as the firm delivered a 34% increase in pre-tax profit to £637.8 million. Announcing its final results for the year ton February 23, the firm said operating margin reached 21.9% and revenue hit £2.9 billion. It opened more than 250 new sites in the 12 month period (2014: …