The military aren't exactly exempt, they can however elect to be their own design authority for a 'mature' type. Where they get to decide what mature means, I believe that's how they got the Jaguar upgrade done without paying BAe the gross national debt.
The MoD have their own airworthiness system which I can only see getting stricter post the Nimrod crash/inquest/verdict.
Well.. yes and no AD. That aircraft is a 400srs (a 419) and they're not that big when compared to something with 'intercontinental' .. wide-bodied size. If one ran into you.. you'd know about it but in the grand scale of things, 1-11 400's are pretty dinky.. let's say small but perfectly formed