Hi hellohowareyou, I can`t give much advise, but I will tell you my story. Instructors are people too and I think you need to find right one to get the most from the lesson. I also had 3 different driving instructors. The problem with switching is when you go form diesel to petrol you need to learn to use gas before clutch, the other confusing thing is that they have different methods of how to do parallel parking (and BSM guy didn`t had tiny convex mirrors so I had to adjust the mirror I were to do a turning around a corner).
And yes good luck with the test (you may only need to do bay/reverse parking ). That is what I had to do maybe because examiners are lazy or maybe because I was lucky I just pulled out and parked perfectly in the bay at the driving center. (I think it is one of the easiest maneuvers for me anyway).
There is other thing called independent driving but I think you can say that you forgot to urn or missed the turning (it is allowed) as long as you general driving is safe there shouldn`t be complaints.
... and the ones that won't