Its also possible i guess for a new pilot to inadvertantly overspeed the MR and actually not fully realise what they have done.
Mmmmmm. This is where we may differ. Even without monitoring the instruments, a properly-trained pilot should hear MR speed climb. The noise change is there - you just have to listen for it.
As most MR overspeeds are done whilst descending, they should be easily avoided.
Similarly, there are a lot of engine overspeeds at start-up. Simply avoided by checking the throttle is closed before pushing the button. If that means you have to look down at the arrow on the collective to remind yourself, then do so. It's a one-second check that saves about £20,000.