Sel, that would be highly unlikely. It is considered rare for a British student not to take a gap year, and it is unlikely that Eugenie will not.
Lam, I don't think that was quite the case. Bea received tutoring at a well-known centre, which is a different set-up (I am speaking from experience having received testing prep from a centre before my stanardized exams). The set-up as well as the goals would have been different.
Kp, Harry was never an academic, but he did receive help for his dsylexia/ learning troubles and, like Beatrice, repeated a year. Harry was working towards very different goals: he was not testing to get into university, he was testing to meet the requirement for his chosen career in the military, and it was therefore not the marks but the passing that mattered. Harry's academic problems were much more quiet than Beatrice's. This can be attributed to the differing views the sets of parents had on how private these matters should be. However, there is definitely documentation of Harry receiving help even while still at Ludgrove. The specifics of this help is largely unknown, because it was not a matter that either of his parents felt needed to or should be discussed with the public.
Harry's passes were a D in geography and B in Art. Before passing judgement on any A-level subjects, I think we should look closely at the course work. Looking at photographs of artwork Harry completed at A-level, I know better than to think that subjects that sound like push-overs really are. Whether a subject is difficult very much depends on the person. (As an interesting side note, Harry's D was not the only D in his year, as was widely reported for many months to follow. It was the only D in geography for his year, and geography had not been a popular subject for Eton in that year. There were several other D's, in other subjects, among Harry's class.)