Dennis qualified as a solicitor in July 1977. Following qualification and working in Central London and High Street practices, in 1986 establishing a well-respected firm, D R Sheridan LLP (formerly D R Sheridan & Co). He is now a consultant with Parker Thomas Solicitors.
He was one of the first 60 Family Law Arbitrators in England and Wales (2012) and has represented clients at arbitration hearings and has also sat as an Arbitrator. Dennis is also qualified as a collaborative lawyer. He specialises in all aspects of private family law and is a specialist in moderate to high-net-worth financial disputes between married and unmarried couples.