Sandra spent her childhood with her parents, including her over-bearing father, in Lisvane. She studied scientific subjects at A level, before moving on to study a physics course at a local university, all at her father's recommendation. Two weeks into her second year, Sandra's father died and she abandoned her course and signed up for the Royal South Regiment.
She was trained and stationed at Caregan Barracks, where she took part in weapons briefings and open water training for sub-aqua. She had a brief but passionate relationship with Tony Bee.
Following the death of Guy Wildman, Sandra visited his apartment where she encountered Jack Harkness and Gwen Cooper. She lied that she was Wildman's neighbour, Betty Jenkins, calling in to look after his plants while he was supposedly away in Egypt.
Sandra was a Christian who regularly attended church. She lived by the mantra of her father, making safe and uncontroversial choices. She always followed the rules, no matter how insignificant those rules were. She was calm, logical and reasonable, but not unemotional.
Sandra had brown eyes and short-cut blonde hair. She was thin, fit and in her mid thirties, with tanned skin and a South Wales accent which Gwen though was Swansea. She wore a mid-length green A-line dress and a pale green cardigan in thin cotton. She paired her outfit with flat-heeled leather shoes and a fitted boned coat in a soft navy-coloured material. (PROSE: Another Life)