Hi Gunny, a flanked unit is in real trouble. Firstly remember that it reads the combat result one line lower than usual on the table, so if the general moderated result was Fall Back, it will go to Take a Break Test. Secondly the fall back move should, as you suggest, be on the diagonal, but it is likely that the next unit along the line will be in the way. Now a friendly unit behind will be forced back too, but it isn't possible to force back the weight of an entire battle line, so the likely result is that the flanked unit will have to break instead. Being outflanked was usually fatal in ancient warfare. This may be one reason why the best troops could usually be found at the end of the line, rather than in the middle, which feels correct to us. Both enemy units would follow up.
"No one ever achieved anything without making a few mistakes along the way"