Thanks Cal, I sorted through them last night into sizes, I saw what you meant about corrosion, I'll be flicking them. However when sorting, most seemed pretty good, but as per your advice I'll test them up to torque spec before I use them.
I appreciate your advise particularly about the bottom half.
I've copper grease for the threads, locktite to use where recommended and gasket sealant. I need to get some surface cleaner.
Cal in the photos can you point out any specific bolts you believe would be suspect?
Or, are you suggesting I should get new nuts and bolts? If you think i should I don't have an issue with that.