In that case keiron I would suggest sticking at a reasonable weight and doing higher reps. Legs can actually respond really well to high reps. Look up a chap called Tom PLatz on google. He had one of the most famous sets of thighs and would routinely squat with 140kg for 50 reps!!

My best with this was about 22reps I think, and I had to go home straight away, without completeing the rest of the workout

Do the higher reps but also do more leg extensions. They are not the most ideal exercise for packing on size, but at least it should take the stress off the hip.