I can think of 2, perhaps 3:
1. The Harrier pilot who it seems stood on his seat firing handle at Yeovilton but hadn't replaced the pins. Fatal accident.
2. The Fighter Controller who managed to bang out of a Hawk over the North Sea. Fished out safe and sound. I watched the Hawk landing at Wattisham - it looked very odd with the pole sticking out of the back cockpit.
3. Details rather hazy, but many years earlier, turbulence caused a Canberra seat to drop with sufficient force to fire the main gun. Sudden ejection came as a surprise to the occupant, who managed to complete the manual separation procedure despite the surprise?