She acquired a reputation as a starmaker, having built hit series around previously unknown chefs, such as Two Fat Ladies with Jennifer Paterson and Clarissa Dickson Wright; and The Naked Chef with Jamie Oliver, for which she won her first BAFTA.
Her other credits include Heston's Feasts, winner of a Royal Television Society Award; Ramsay's Kitchen Nightmares, winner of two BAFTAs, an International Emmy and a Grierson Award; and another food-related TV series, The F Word, featuring chef Gordon Ramsay.
Llewellyn also acted as co-producer of several American cookery and reality television programmes, such as Kitchen Nightmares, Masterchef, Hotel Hell, and Masterchef Jr. Llewellyn had success finding on-screen talent outside the culinary world: the BBC2 series Mary Queen of Shops launched the career of television presenter Mary Portas; and Two Men in a Trench, also for BBC2, introduced archaeologist and historian Neil Oliver to television audiences.
Llewellyn was also executive producer for The F***ing Fulfords, a BAFTA nominated documentary for Channel 4.
As the managing director of Optomen, Llewellyn led the company through a period of rapid growth.