I suspect the Nav Rad was more at risk from an explosion in the starter system !
When I was on 30 Sqn (Hercules) one of the pilots had flown the Javelin, with 33. He and I had several discussions about aspects of the a/c. He said that the first time he fired the guns at night he was blind for a week ! He also diverted into Heathrow with an emergency. The RAF sent the groundcrew and spares down by train including a container of Avpin ! I should have remembered this story before I mixed up the various starting systems.
The president of 30 Sqn Association had tested the Javelin when it was to be introduced into service. He was not very complimentary about Glosters when I asked him about his experiences.
A very good read about the Javelin is 'The Quick and the Dead' by Bill Waterman