An extraordinary milestone has been celebrated at a Kent nursing home where four residents have chalked up a combined 401 years. Three of them are centenarians and another will celebrate her 100th birthday next month. On Tuesday, it was Cecil Smurthwaite’s time to turn 100 which was marked with a party at the Red House Nursing Home in Canterbury. And among the special guests invited to celebrate with him were fellow residents 100-year-old Joan Allson, 102-year-old Margaret Lewis and Pauline Ventress, who will be 100 on July 13. Another resident who would have been welcomed to the party was 103…