Made a few changes today.
AI currently tracks where it's units are, and where recent deaths have been (graphics down the bottom right).
It also sends units out in 'patrol' mode to try reach the other side, but they stop if they notice an enemy nearby.
Units now track whether or not they're hitting their target. If they miss too much they will pathfind towards their target.
Units also give up on chasing earlier, switching to closer targets if there are any.