In reply to shaymarriott: How did you find the middle wasn't the middle? When lap coiling it from the middle? I do this all the time, and think "that marker is never in the middle!", so I start from the two ends together and go through it carefully - and find invariably it is in the middle.
I think we all just let a bit one half of the rope slip through our fingers when lap coiling then it *SEEMS* the middle marker isn't in the middle, but it probably is. Throw it down a 25 mtr cliff with the middle marker round a tree and see what happens!