Retreat hell, we just got here!

[triangular_cube]

"I get it that during an assault the unit(s) must go the one square back immediately, attempt to recover the next turn and then retreat if unsuccessful"

Depending on what you were saying this could be wrong. They don't immediately retreat from the assault hex upon becoming demoralized, they do when they fail a recovery roll, which they must be activated to attempt. 

2 oft missed special cases to consider as well, if they are surrounded by enemy units and they must flee, they are eliminated. And they do not HAVE to flee if they are in an entrenchment, but they may if the owning player so chooses.