I'm a vegetarian and I looked into this stuff a while back. The Examine.com page What beneficial compounds are primarily found in animal products? is a useful reference with sources and includes the ones you wrote above. An older page with some references is this one.

Thanks, this looks good. The sort of thing I was after.

I had a basic panel done

I've never heard this expression! I wonder whether that's just transatlantic terminology variation. Will look into whether I can get this on the NHS.

Excessive amounts of creatine (look up "loading") is recommended for bodybuilders but 5g/day is recommended for vegetarians. See gwern's review and the examine.com review.. The examine.com review mentions that the fear of this compound is irrational and recommends 5g a day for everyone, pointing out that creatine would have been labeled a vitamin if it wasn't produced in the body.

Perfect; thanks.