Here is the rule for Pinning please read carefully

It is not permitted to pin an opponent for more than 10 seconds, for example, where one robot pins its opponent to the arena side or floor.

After the robot is released the opponent must back away.

It is bad sportsmanship to continually pin an opponent intentionally

however it is understood that some weapon designs may necessitate this
.
Robots that utilise a crushing or gripping design to hold their opponent must release within 30 seconds.
In the event that both robots become entangled the fight may be stopped and the robots separated
.
During melees both of the entangled robots may be deemed immobile.

My question is how far should the robot back away, dose this mean the opponent should be permitted to get back on their wheels before the fight starts again.

I don't know the answer to this the rules aren't clear, at the moment the robot that has been stacked on the side, the other robot backs away and then pushes the stacked robot before they are mobile, this dose comply to the letter of the rule but the robot that is immobile can't get going again.
with Saint, Gabriel and even Cherub this hasn't been a problem for me. but it would be nice to clear up this point before the competitions.