I think it's important to note to IC hopefuls reading this thread that STEP is becoming more and more standard as the quality of applicants surges through the roof year on year. With everyone doing great in their exams, the admissions team need a way to differentiate between candidates.
Don't let that scare you off, the course is still just as hard, so you better get used to self study. Being able to complete STEP is a great setup to success here, mostly with the study ethics you will need rather than the maths itself.