[X] Go over the wall. Between Archer's range and hopefully Goemon's talents, as well as your chains, you're well suited to striking from behind. If Jeanne can function as a distraction, you might be able to do more damage coming at them from a different angle.
[X] Take your Servants and charge through the gate instead. Between yourself and Circe, you've got the better defense. If something is going catastrophically wrong right inside the door, you two should be able to handle it and let Jeanne's party get into the city without issue.