LONDON — Larry Dalzell, one of the West End’s most respected theater agents who repped a raft of thesps including Ralph Fiennes and Michael Gambon, died on Sunday aged 78 following heart surgery.Dalzell, who was born in Glasgow in 1933, worked with a range of leading thesps in stage, film and television throughout his career including Gwen Ffrangcon-Davies, Ciaran Hinds, Alec McCowan, Eileen Atkins, Jason Robards, Edith MacArthur, John Castle, George Hearn and Bernard Lloyd. He also developed a stellar list of helmers and designers, including Ronald Eyre, Peter Dews and David Walker. Dalzell’s career started as a child actor in Glasgow, where he worked with the Citizens Theater before becoming a professional thesp with Edinburgh’s Gateway Company, and then toured with the Wilson Barrett Company. In the 1950s, he continued his acting career in London before he joined the Dennis van Thal agency in 1962 as an agent. Four years later he set up his own company, Larry Dalzell Associates, where he quickly gained a reputation in the city for his integrity and loyalty to his clients. In 1998, he joined forces with Simon Beresford and set up Dalzell and Beresford. Their client list includes Fiennes, Hinds, Lindsay Duncan, Richard Griffiths, Matthew Goode, Diana Rigg, Michael Ball, Elena Roger, Jamie Campbell Bower and Laura Michelle Kelly. The agency also boasts Tim Woodward, Helen Lindsay, Scarlett Strallen, Sarah Brightman, Joseph Drake, Ben Mansfield, Jack Ryder, James Fox, and David and Hannah Yelland as clients. After more than 40 years as an agent, Dalzell retired from the biz in 2004 and lived in Brighton, where he died on Sunday. There will be a private funeral followed by a memorial service in London later in the year.