Focus on the mooks, preferably with combos, counters and takedowns. Even if the visual sign that you can counter doesn't appear, the enemies often will give hints that they will attack. Always keep an eye on Bane. If he throws a rock, dodge quickly to the less crowded side. You can dodge over the henchmen (which will also stun them quickly). If he charges towards you, use Quick Batarang and then dodge to the side. He will crash against the wall and be stunned, when that happens, focus on him and forget the mooks.
With some practice, you can chain all of these actions in the same combo and keep the flow, which will increase your multiplier greatly and allow for easier takedowns.