A London-born actress who earned the inaugural scholarship to East 15 Acting School launched her career with the Ken Loach-directed series Diary of a Young Man, written for her by John McGrath and Troy Kennedy Martin. She broke through in the 1980s as Dolly Rawlins in Lynda La Plante’s crime drama Widows and its sequels, a performance that secured the 1984 Pye Award for greatest television impact.…