Watson-Miller is the daughter of Herbert Schek, a prominent German motorbike enduro rider who became German, European, and World champion and started the Dakar Rally fifteen times. Growing up with racing machinery and technique at the centre of family life gave her direct and sustained exposure to competitive riding from an early age. The Schek-BMW bikes on which she won her first two Dakar ladies' titles were built by her father.
Watson-Miller studied business informatics at the Hochschule Konstanz and earned a master's degree in informatics. She later settled in London, working as a business manager in financial services.
Watson-Miller first entered the Dakar Rally in 1988 but was forced to retire before the finish. She returned in 1990 and 1991, winning the ladies' cup in both years aboard the Schek-BMW machines her father built, taking back-to-back titles.
In 1992 she entered on a Suzuki DR 350 and finished second in the ladies' category, behind Jutta Kleinschmidt riding a BMW R 100 GS. Kleinschmidt, then a private entry, would go on to become the first and only woman to win the Dakar Rally outright — which she achieved in 2001.
After a pause from competition during which she had two sons, Watson-Miller resumed racing and won the FIA Cross Country Rally World Championship Ladies title in 2005.
She entered the 2006 Dakar Rally on a KTM EXC 525. She was involved in a heavy crash during the event but continued to ride, eventually finishing 67th overall — a strong overall position in a field of professional and semi-professional riders — and winning the ladies' cup for the third time, completing her career total of three Dakar ladies' titles.
The 2008 Dakar Rally was cancelled due to terrorism threats against the event in Africa. As an alternative, the Trans-Oriental Rally was organised, running from St. Petersburg to Beijing — a route spanning several thousand kilometres across Russia and Central Asia and among the most geographically ambitious rally raid formats of the era. Watson-Miller competed in the full event and finished 19th overall, a result that placed her competitively against the general field rather than solely within a ladies' classification.
Watson-Miller's career combines a lineage of pedigree motorsport — through her father's record as a multi-titled enduro champion and fifteen-time Dakar participant — with her own sustained record at the top level of women's rally raid competition over nearly two decades. Her three Dakar ladies' cup victories span different machinery, different eras of the event, and different competitive contexts, reflecting consistent performance rather than a single peak season.