I am only answering because no one else has...I don't know whether or not you can get old results now. I guess you're doing pretty well at school if you are helping your cousin out, so does it really matter now how you did all those years ago? Perhaps if you mention the area you live in, someone will know, but maybe some things are better left where they are. If you didn't pass, that doesn't mean that you won't go on and do really well in your GCSEs, just as if you did, it is no guarantee that you will. It's all down to you and what you put in...these tests are no indication of the person you are.
Good luck to you and your cousin,