He was given the BAF Award of Merit in 2007.
This from the Wimbledon Fencing Club website -
"Mon 05 Jan 2015 - Derek Sweeney passes away at 85 It is with great sadness that we announce that Derek Sweeney, Life President of Wimbledon Fencing Club, died Monday 5th January 2015 in St Helier Hospital. He was 85 years old. Derek joined Wimbledon Fencing Club soon after its formation in 1951 and was its mainstay and principal coach for much of the time until he retired from coaching about eight years ago. He remained a great friend to many of us."
He also did great work coaching paraplegic fencers, among whom Caz Bryant (now Walton) gained medals in several Paralympics.
More information can be obtained from Joe Shackell firstname.lastname@example.org