hey i'm resitting this year, you can go through the 2 years again with your school or you can resit them privately, costs are quite high for each exam... im paying around 1k (CRAZY) but that's cause I applied past deadline,before deadline I'd say maybe 500-700 for 3 a levels? also if you're lucky and have some schools near you that allow private candidates you might get better prices. When it comes to getting predicted grades that's harder but there's some online courses (which cost money on top of them arranging the exams for you) which is kind of like online school but chill? and they'll give you predicted grades for uni.You usually apply by filling a form and if you wanted to resist them next year then you have plenty of time to apply (just make sure you do it by like early) january the least to be on safe side