Persimmon PLC ( LON:PSN ) chief executive David Jenkinson has handed in his notice as the housebuilder reported flat profits and said it was not going to step up its capital return plan. Having already posted a year-end update showing a 4% fall in housing volumes and flat average selling prices, the FTSE 100 group said revenues came out 2.4% lower at £3.65bn and profit before tax down 5% to £1.04bn.