He is a member of the Society of Trusts and Probate Specialists (STEP), the Association of Contentious Trust and Probate Specialists (ACTAPS) and the Society for Computers and Law (SCL).
Leigh is the Chairman of the STEP Digital Assets Global Special Interest Group.
He is an editor of chapters in Williams Mortimer & Sunnucks on Executors, Administrators and Probate, including probate claims and administration actions, procedures towards obtaining grants and the administration of digital information. He is contributor to the England and Wales section of the STEP Directory and Yearbook. He has written a book called The Digital Estate, published by Sweet & Maxwell.