A Second World War heroine who trained Britain’s fighting force is marking Remembrance Day with thoughts of lost friends and loved ones. Dorothea Barron, 100, served as a visual signaller in the Women’s Royal Naval Service (WRNS, and known as the Wrens). Lying about her height, she joined up with the Wrens in 1943 aged just 18 – and was posted in Scotland to teach men bound for Normandy how to use flags for communication, known as semaphore signalling. Eight decades later, she will join millions more Britons in silence on Remembrance Sunday. “I feel very proud that we’re still remembering thos…