mewsie
I am also a PPL student and I was slow to get to grips with the circuit side of things. It took me longer than I thought to get to solo stage and even now it is an area that needs work.
Until you get to the stage where the majority of your approaches are 'good' you don't get a sense of whether the approach you are on 'looks wrong'.
The good news is that over time you will get better, then it should click into place. Also, because you are getting better at the different stages of the circuit, you will start to be a bit more 'ahead of the game' and not having one thing after another to deal with.
Basically I believe that anyone can get there with practice. However as you are finding, for some people it takes longer (and hence costs more).
The thing to remember is that you chose to learn how to fly so that you could fly planes, and you are still flying a plane, you are just having to have an instructor there for a bit longer than the 'average' (whatever that is).
If you feel you want more from your hobby than circuits then ask to do some navigation exercises once in a while.