That is pretty much what happens. Just another way for the CAA to make money out of all us 'Poor Pilots'.
The only possible way that you may get a different result is if you wrote a note to the examiner about a certain question that was in the paper that you beleived that there were two answers!!! I don't think that they read them sheets of paper anyway!
I would just bite your lip and spend that £40 on re-sitting the paper!