To be honest: I haven't much to say about this episode.
Luckily, Bark appears here and becomes a strong ally for Watership Down. The end of the episode, when the others try to save Fiver and she doesn't fight against them and wants to surrender while Fiver tries to stop his friends isn't bad.
But if that and the friendship/alliance between Bark and the rabbits wasn't part of the episode, it simply would've been another filler.