NVQ Web - Health and Social Care

Hi  Having lost my original assessor I am finally up and runnig again on my NVQ3, working with vulnerable adults in the community.  Could anyone help me please on a couple of queries.  What are moral rights? What types of evidence are valid in investigations and court?  What actions and statements could contaminate evidence? I have vague answers but not enough detail in my head.  Thanks to anyone who can guide me.    Dee