Oh dear sorry to hear your news West Kent. This happened to a friend of DD1. He successfully retook 2 A levels with the intermittent help of a tutor (ramped up towards the end). The deal was he had to pay for the tutoring himself, which meant that he focused on both work to earn the money to pay for the tutor and work to pass the A levels as he was, paying for them himself. I think this helped with the self motivation. He went from a C and a D to two As, which is what he had originally been predicted. He has just graduated with a 1st. However, his results were a huge shock and he had to take a good look at himself and reflect that he had not worked as much as he should/could have. She has another friend who retook, whose results were hardly better, but she was someone whose (parents?) aspirations/expectations always seemed to be higher than others' (ie the school).
Before making a decision I think it is important to consider why this happened and what would be different in a re-take scenario.
Given that your DD has already planned to take a gap year you/she have time on your side, so can use that to reflect and decide the best course of action.
Good luck, trying times and wishing you well
