Lesley is the head of Penningtons' private client team. She joined the firm as an articled clerk in 1972, qualified in 1975 and became a partner in 1978. Since qualification, she has specialised in private client law, advising families and individuals on strategies for mitigating tax exposure, involving the use of tax efficient structures, wills and trusts, for both UK and international clients. She also has experience in the field of charities and heritage property. She is a member of the Society of Trust and Estate Practitioners (STEP). Lesley is also General Editor of Butterworths Wills, Probate & Administration Service and the Revision Editor of its Wills Division.

Citywealth magazine has listed Lesley as one of the top 20 women in private wealth management, as well as one of the top 20 people in the 'Leading lawyers' category in its latest guide to the most highly regarded figures in private wealth management. In 2010 she was the winner of the inaugural Citywealth Editor's Choice Award. She has been named as one of the 50 Most Influential Private Client Practitioners in the Private Client Practitioner 2012 list.

Lesley became managing partner of the firm in 1997, changing her role to chief executive on the conversion to an LLP in 2005. She decided to step down in 2008 after 11 years in the role. She also headed the firm's Private Individuals Division between 2007 and 2010.