I wouldn't really worry about it. As has already been mentioned, it's important to have an appropriate answer in case an interviewer does ask you why you failed so many exams.
RYR do require first time passes as a previous poster has mentioned. I and a few others did not get through the RYR assessments and the one common factor was that we all had second series passes in our IR's.
Still didn't stop them from charging me £260 for an interview and 10 mins in the sim...
It paid the interviewers salary for a "hard" days work...who...mind you didn't even bother to turn up on time on the assessment day!
Rant over!