From the Test Flying Memorial site (via Google)
http://www.davidsiddall.com/testflyingmemorial/1946-70.htm
DATE: June 8, 1951
TAKE-OFF POINT: Boscombe Down, Wilts
CRASH LOCATION: Seven Barrows, Wilts
AIRCRAFT TYPE & SERIAL: Westland Wyvern TF Mk 2 VW869
CREW FATALITIES: Lt-Cdr (E) D.K. Hanson
PURPOSE OF TEST FLIGHT: Air test following propeller change and reported vibration
ACCIDENT DETAIL: 45min after take-off aircraft broke up following canopy failure. Pilot ejected but was severely injured by control column as seat left aircraft. He was unable to release from seat and use his parachute.
Hope this is the one you're looking for.