So here's what happened anyway. I sent some tribesman across to provoke a response. None. The enemy just kept reforming into column formation. I sent my horsemen across via the ford to the south and carried out a few charges on their column. Nothing. They kept reforming. So I got the poops and sent my entire army in to attack, and took out the first couple of enemy units - the enemy kept reforming. The Romans had silver armour & weapon upgrades so I was losing too many men for this to continue.
So I did this
I sent my entire army through the gap and up to the rear where the Roman general was, and killed him to gain an advantage. Then rested my men. Then war-cry and attacked the next unit down. Rested. War-cry. Next unit etc until one by one I had destroyed them and ended up back where the violence began, at the bridge. See here how they retained column formation throughout.
And the end result
A very costly 'bridge battle exploit".
And to top it off, that same AI turn another army attacked me and I was forced to withdraw.


Oh well. Hope you enjoyed my little rant anyway