A former HMI, Marion is also the retired headteacher of James Allen's Girls' School, an independent school in Dulwich. Marion received a CBE in 2012 for her partnership work between the state and independent sectors across South London, including the Southwark Schools Learning Partnership which she founded in 2003 for 10 Southwark secondary schools and which still flourishes today. She is currently also a Trustee of Classics for All and the Charleston Trust.