Info required on my ejector seat

Does anyone know what aircraft this seat is from ?.
It is stamped-

SERIAL # 1.
TYPE 4BBD “UNCLEAR”.
MARK 1.
DATE 12.5.65

It’s available for exchange, should anyone have any pre 1935 (especially WW1) instruments, compasses, aircraft fittings, aero-engine parts, manufacturing drawings, aircraft grade Ash/Spruce, S3/S510 etc steel sheet or AGS turnbuckles/wire furrules/ streamline wires etc etc.

Cheer’s.
Bob. T