We tend to wing this depending on the circumstance, but usually the attacker has had only one wound.
If the target was 2" from a height, we treat it as a failed charge and the charger is 1" away. If the target was next to the height we place the charger in base to base. It still counts as a combat but the charger loses the strikes first. If the charging model was knocked down or stunned by the fall it goes badly from there.