As skylinegeoff said, you had a situation of perceived danger. That is you felt the 4WD was threatening you. Tell the court just what you put in your first post. Even better have it written down and read directly from it. Explain that you informed the officer that pulled you over of the 4WD and that is why it is mentione dbriefly in his statement.
The thing you have to decide tomorrow is as Abo Bob said, adjourn or go through with it.
Either way, get a haircut, shave, wear a suit and polish your shoes!!! (This DOES make a difference)
I reckon you have a fair crack if you get a decent magistrate.
Good luck!