Hello,
I was an engine fitter at Boscombe Down in the middle fifties and was involved in the maintenance of the Javelines there (WB 827 ?? 544 ??).
Anything specific you're looking for ? I could try dusting out my brain cells.
(I think I can put you in touch with the pilot who accidently ejected - it happened on a several occasions - and when trying to release himself from the seat, released his harness and decended several thousand feet simply hanging onto some canvass webbing !)
PM me.