I got the idea from my experience that they weren't too interesting in looking for people that genuinely care about the environment, they are looking solely for people with perfect sales skills regardless of your passion. The interview was ok, there were 4 of us and they let us speak separately, there wasn't any pressure to speak first or when called upon which was nice. It's really important that you read the document they give you, as they do ask you questions on it and give you little time to prepare for the role-play. You have to nail this. They asked competency based questions and look for your confidence. After the questions we had to go away for a couple of hours, come back and then have a practice run of door canvassing, you had to be perfect first time, with no hesitation. The role play and practice are essential to get right.