My experience as an instructor is if ia student is not progessing in the circuit than the problem is weak fundamental flying skills. Poor attitude control is the usual problem manifested in the nose contunually nodding up and down on final with the airspeed never stabilized on the proper value. This is often combined with way too much power on final and therefore execessive airspeed into the flare. When the power is chopped it all goes to hell.
My 02 cents. If your circuits are not getting better than go to the practice area. I think this is even more important for students who do not fly regularly
as skill fade on the fundamentals will set in. It is hugely more efficent to fly regularly when taking lessons , so much so I recommend you save up enough money to get at least the first half of the course done before starting your PPL lessons.