AQA Spanish paper went from an E to a C and overall grade from a C to a B.
I think they just forgot to read the second half of my essay...
I would generally advise only remarking if the mark looks really weird and out of sync with the others. If you were expecting an A and got a high B, there probably isn't a marking issue. If you were expecting a B and got an E, then it's probably worth having it checked.