What shall I do?

So I've just had my As levels back and did average in a couple and pretty badly in some others. My parents want me to retake the year but I was thinking if I retook and got A's let's say would universities such as UCL or LSE still consider me even though it took me an extra year to do a levels

It depends on what course you want to do I think, have a look at their websites for the course you want to do.