I was unaware that I could make a claim for hearing damage, as I had been advised by a solicitor that, as most of my time in the RAF was covered by Crown Indemnity, I wouldn't be able to claim.
I can only speak from personal experience and legal advice I was given as a programme manager. In the context of aircrew hearing loss, the litigation clock started running in 1996, when a viable solution was developed, trialed and accepted. (Analog Active Noise Reduction). Part of this was offering aircrew made-to-measure helmets. Another immediate change was to the type of earshell padding, which offered greater protection to those with spectacles. Another proposal, using decent (French) transducers, was rejected on cost grounds, although the funding was there. That applied, at the time, to the Mk4A helmet. If pressed, I'd say there is absolutely no excuse for aircrew or groundcrew being exposed to excessive noise dose after 2000. If you search ANR in Hansard, you'll see Mike Hancock MP (Portsmouth) asked very pointed questions in the House about this, concerned about litigation. Janes' ran a very good article, citing the drop in allowable flying hours, to around 60 a year in helicopters, without protection. Hitherto, this had all been made difficult by tables of indecipherable decibel notation. If you decide to take it further, give me a shout and I'll provide the papers.