Managed to finally complete Mission 5. I simply set up the Cavalry and my Commander on the flank to face the clanrats and the Rat Ogre.

I used my wizard to slow the stormvermin, crossbowmen to pick off clanrats to relieve the dwarfs and sent my infantry to reinforce them.

A lot of luck and good fortunate, but, something else I enjoy about the game, over in a matter of minutes.

Just happy now I don't need to see the flailing armed Rat Ogre rabidly chasing my army to death,