Her most significant mentor was Marie O'Regan, a French-Armenian designer who had previously worked on creating model millinery for Christian Dior in Paris. O'Regan was not only her tutor at both the London College of Fashion and Royal College of Art but also remained a close mentor until her death, with Philippa continuing to receive millinery lessons from her almost until the end of O'Regan's life.

Philippa worked for Mr. Somerville, the Queen's milliner, where she learned the trade from the ground up, starting by making tea and working in the workrooms. In 1991, she launched her own millinery company from her bedroom, quickly gaining prestigious clients, including British Airways, for whom she designed hats as part of a year-long project.

Her professional journey included working in Italy with Grupo GFT, which represented major fashion houses. She established the Tiara Gallery and developed a successful business with a shop in Pimlico and a concession in Liberty, specializing in tiaras, veils, and hats.

After having her first daughter, Philippa adjusted her business, relocating to a smaller studio in Camberwell, Clockwork Studios, to balance her professional work with family life. Throughout her career, she has collaborated with numerous renowned designers, traveled internationally, and taught millinery at various colleges across the UK.