Fighting Enemy Camps with Leaders

I am trying to defeat the final area of my home camp. I have a bandit leader camp with only 'Wild Mary' remaining. I am trying to defeat. I have just sent two waves of troops, the first with a General and 200 Malitia, and the Second with A General, 80 Malitia, 50 Recruits and 70 Cavalry. The simulators I had consulted first suggested this would be successful in defeat of the camp.

I sent both within seconds, the 200 Malitia arrived first, and defeated the leader to much less than half strength, however when they were defeated, the leader managed to instantly regain her strength, and of course the second troop failed too....

Any idea what happened here? Understand that the bandit leaders manager to regain their strength after surviving a battle, however is this meant to be occurring instantly?? How else could I defeat this camp.

Loving some help as rather annoyed with this occurring after spending a lot of time training this level of troops.

As far as I'm aware any damage done in one battle is lost in the next, same applies to your own troops when they return from battle (if they have taken damage but not been killed)

I don't know what simulator you were using, but it is clearly wrong.
As mary is a Boss, she regenerates her HP, so the "first wave" is meaningless, unless it kills her outright.
If you look in some of the guides, the ideal setup for Mary is mentioned in several places, once you have removed her troops, it has to be a 1 wave victory.