Rena Barbara Gardiner was born on 4 April 1929 in Epsom, Surrey. Her parents, Robert Charles Gardiner and Ellen Caroline Devitt, had married on 18 April 1927 at St. Giles Church, Ashtead. Rena (who was named after her father’s elder sister) spent her early years in Ashstead at West Hill Villa, and then the family moved to Maidenshaw Road in Epsom. Rena’s younger sister, Maureen, was born in September 1933.
Her father was an electrical engineer and her maternal grandfather, who lived near the family home, was an enthusiastic and able amateur historian despite a lack of formal education. Both men had an influence on the young Rena. As an engineer, her father was fascinated by machinery and had an instinctive skill for taking things apart and mending them. He passed onto his daughter an ability to understand machinery, in her case printing presses, and how to repair and maintain them. But he also had the ability to draw – in a precise technical style rather than with artistic expression – which nonetheless inspired Rena. She was very close to her grandfather and it was probably he who instilled in her a deep love of history.