After A level/GCSE exams have been marked and the certificates given, can they ever be remarked without being asked and and your grade lowered? Or could the qualification be removed should malpractice in that exam be found in the future after you have been awarded the A Level/ GCSE certificate?
Note: This is just a hypothetical situation I'm interested in, it has no bearing upon me at all, though it may be useful advice for others.
No and no. Whatever grade you get is final. I've actually had a first hand experience of this.