I've merged the threads.
Something I did not understand in all this: one of the 3 Panzerjaeger kept "We can't continue to fight" and I had to keep turning him around and putting him back in position. I don't know what his problem was, his morale etc all seemed to be okay but he didn't want to know.
It was damaged or maybe the commander was killed. In this case units will "We can't continue to fight" and try to disengage and retreat. You can hold them by giving the Stop order, or another order, but this isn't for long.
At the end though all I got was a Minor Defeat, I think because I spent too much time around the school clearing trenches (using Panzerjaeger as artillery). I took too many turns doing that and I did not make any progress across the map during them. I am not very good at attacking and prefer defending, which I like to do in the quick battles and that is where I learnt a lot by setting up defences then playing them over and over giving the enemy slightly stronger units each time so I can see the limitations and tactics required.
You are right, Minor Defeat is due to slow attacking. Each key point held adds some amount of victory points each turn. So, your main goal in operations is to keep your key points, and to capture the enemy's (or "neutral" if there are any). Keep constant pressure on the enemy.