Absolutely true! Avon shows up in episode 2 and there’s no Blakes 7 without Avon.
https://iment.com/maida/tv/b7/b7characters.htm
https://iment.com/maida/tv/b7/b7episodeguide.htm
YouTube Playlist
https://www.youtube.com/playlist?list=PLYTtL1FB2XCrdxh8T1JV2vn43QOMLswZ2
Comedy Tonight
https://youtu.be/WA5OaVFePbU
What about Servalan?