Do Exam Boards Take Situations Into Consideration?

Not an expert on this, but I don't think exam boards have any leniency on grades for any situation except for administration issues such as errors in exam papers. For learning disabilities like dyslexia you can get extra time, but your overall grade won't be determined separately to other students. What you can do, however, (if you were requiring for example certain grades to enter a sixth form college or for when you're applying for uni) is to tell whatever institute you're applying to about your "exceptional circumstances." This might involve filling in a form or proving how your conditions have affected your performance.