Thanks all - will be doing a little further reading with that Genghis.
Certainly clearing up a few things I've wanted to know.
One thing India touches on is the possibility of unseen or latent damage caused earlier in the a/c life - mulled this once after whizzing around at 3+g during hour building after getting bored with S + L practice. I was always honest about what I'd been up to but who knew what had really happened to it in the past.
Good to know it had probably been accounted for.