Hangarshuffle...
Early Type 4 seats - can't remember the sub-mark but they were very specific to Sea Vixen. ISTR some kit associated with underwater ejection from my Fitters Course at Halton in '76. We had a Sea Vixen in the Armourer's hangar on the Airfield used for Seat Fits and Removals, and Weapon load training. Getting the Observer's Seat into and out of the 'Coal Hole' was interesting!