Thatcher left chemistry after only a few years, returning to school to study law in 1952. Despite the brevity of her career, Britain’s premier scientific organization honored her with a fellowship in 1983, a controversial move that reportedly irked some British scientists. Sir Andrew Huxley, the president of the Royal Society, told the New Scientist at the time that Thatcher’s “interest in chemistry has continued” since she left the field.
Thatcher did, notably, invoke ice cream as a symbol of European over-regulation in a 1978 speech.
“The idea of European unity is a grand concept,” she told Les Grandes Conferences Catholiques. “But the cause of unity is surely not advanced by hundreds of petty internal regulations, such as on the content of ice cream or the activities of doorstep salesmen.”
Update: Daniel Fromson, writing at NewYorker.com, looks into the history of Thatcher's role in the development of soft serve, arguing that the story "resides somewhere in the hazy borderlands between simplification and legend."