The easiest thing to do is to force them to come to you. Engage from range with 1 character and run back into the tunnel and force them to come to you in waves rather than all at once. This makes it a lot easier. Position your team around the corner in the tunnel so they dont get hit right away and you can get a cheesy 1st attack for free if you want.
I also noted that you still have not saved Gereth which should have happened before this particular fight. You seem to have skipped this somehow. Saving Gareth and talking to NPCs will get the collars removed from everyone. The dragon area should be nearly the last thing you do before you leave the island.
Last edited by Marc54; 31/10/17 12:24 AM.