Can you request to get your coursework moderated/remarked?

With my History A Level coursework, now I knew I wasn't going to get an A but I thought I was pretty capable of getting a B. I wouldn't have minded getting a C even but it turns out I got 42/80 in the end which according to the WJEC website is a D grade!
I don't know what was so bad about my coursework, I interpreted every source in the correct way as far I am aware and thought I had quite a solid argument for the statement.
My teacher told me it was good in the few weeks before I handed it in, that I was getting there and that when he did the final mark I should get a good mark for it. Then he went and gave me a D. There's only 8 in the class and another person got 35 and someone got 37 aswell! I think only one person got a high mark which was 63/80 and she's an A student. I feel really let down to have come out with a D and I put so much work into it from September to April, and it's really going to drag my A Level down now, I'm going to struggle to get a B.
So is it possible to have an examiner mark it or something, I know you can get papers remarked. Would I be able to request it now or would it have to be after I've got the results of the whole thing? Thanks.