I did them both, thought the biology one didn't go as well as the chemistry one, but I am through to the next round of biology. I really enjoyed the chemistry one though, but as only 10 go through I doubt I'll make it!
i did the chemistry olympiad too. my teacher said i managed exactly half marks, and now its been sent off. i thought it's centre marked first like mine was. only 10 ppl! really?!
No, my teacher said that he had a mark scheme but was not required to mark unless he had more than 5 entries and he only talked four of us into sitting it. I saw him today and he says he has been promised that they'll be back this week.