If you want to resit your a levels, you can either do a resit year were you go to school like normal and be in the same lessons as the year below you, or you can do your revision at home and just come in to school to do your exams. This will depend on your school though, contact them if you are able to resit your exams, they will tell you if that’s fine and you’ll choose from the 2 options above, not all schools will allow you to retake with them, therefore you will have to resit your exams as a private candidate, this will mean you pay to resit each subject in a private exam centre and just come in to complete those exams(it costs roughly £350 per subject, but don’t be out of by that price as it is for your future and you could get a part time job from September to end of December to pay it off, leaving the rest of the year to really revise for your exams).