done with the previous save!
new save: https://forums.totalwar.org/vb/local...id=193&id=4248

actually there was a unit of Hoplites outside the city, when I attacked it, it coaxed the garrison out of the city and onto the battlefield, and I was very fortunate to have a very nice battlefield that was a large plain with some light forests at the sides. and what's more fortunate, the cavalry charges were all superb.
I'll just carry on with my battle report. (making it IC)