Hey. I am in year 13. It depends what you want to do at university. The best thing is to pick subjects that are the most relevant to the degree you want to do. Picking the hardest is not always the answer, because i picked Maths, Further Maths and Computer Science (already done Russian A Level), execting to get into UCL and Kings; however, the grades where not good enough for those universities. My 1 offer from university specified what grades they want from what subject and they did not include Russian ( the others allowed Russian A Level) If you speak it fluently the A level Russian is not hard. I struggled alot with the writing as i didnt revised for it much but I got an A. Once again, you can get in to Russel group university with BTEC subjects, its the relevance what matters the most. However, if you dont have required A levels, universities might look at other factors, Personal Statement or extra things you do outside school, or might put you on extra exams like STEP paper (if you want to do maths). Also universities like UCL really value people that know an extra language, having qualification is even better. If you get that A level, 1/3 of your A levels are done. so either way its win for you.