Former Student Perspective
When I was training, there were a few glaringly obvious factors which led to students failing.
1. The 'agency' i went through were very unsupportive towards students and tutors - did not provide sufficient resource materials for OSCE/written prep etc so when the OSCe's happened, we were all in shock
2. The 'agency' was more interested in taking money from students. One of the basic requirements for the course was to be able to communicate in English to a particular level...half the students in my class struggled with basic English, so it was not surprising that they were unable to grasp the terminology or understand what the questions were asking or keep up with the pace of the lectures.
3. My tutor was brilliant. She was always well prepared, her lessons were detailed, she sent us useful video links to expand on topics etc She went above and beyond to help us as much as she could even when the 'agency' didn't fund the required resources. One of the other tutors had a whole class who failed and they joined our group for the next lot of exams, and it turned out that they were not taught half of what we had learnt with our tutor.
4. Lack of past papers and unrealistic OSCE practice
If a whole group fails, the above are certainly things to consider. Was it the teaching? Was it the students understanding? Was it a language barrier?
Out of 25 of us in my original group 13 dropped out and 5 failed due to language barrier. So, in terms of pass rates, I think it depends from college to college, tutor to tutor, and the body of students.
I hope this gives some insight?
Hopefully your college is more supportive.