I never said shields could not be used against chariots. I said the extra parry bonus could not. You do know what a parry is don't you? As it relates to warhammer. blocking a lunge or deflecting it with a circular motion of the sword. I don't see how a "parry" can be done to an impact hit. However as a RAW, I can't find anything that says you don't get it so you must. I guess it's just common sense that you wouldn't
I referred to it as the hand weapon and shield bonus in my last post. "Parry bonus" is just a slang term for it, and apparently this slang term has caused you the confusion. If it was really a "parry" bonus, wouldn't you get it if using a hand weapon and no shield? Or how about two hand weapons? Just think of the +1 to the front as a shieldwall or something. If the fluff visualization isn't appealing, substitute your own. But rules are rules! If you want to negate the parry bonus, try outmanuevering the opponent and hitting their flank... Speaking of rules not matching reality, I think halberds should work like spears in the second rank, since they can be used as poleaxes OR spears in reality. Maybe make them lose the strength bonus in the second rank or something... Certainly would make Temple Guard a very killy unit!
I assume you would get the bonus as it is a bonus depending on what you chose to use, not what your opponent chooses to hit you with. of course it is only to the front, but if you got flanked by a chariot you have already done something wrong, or had something go very badly for you