I just finished part 3. I thought the process was fascinating.
Part 1: only Paul is engaged in the production. John is completely disengaged, so Paul has to lead and make arrangements which pisses off George. George leaves the band.
Part 2: John realized the bands falling apart, so takes the leadership role. they agree to skip the TV show and George returns. What follows is the very best part: creative music-making process. The way John & Paul play off each other, with George trying to make contributions.
Part 3: revolves around the roof top show. It’s significant that George tells John, after Paul leaves for the night, that he wants to make a solo album.
Great all round series, but part 2 is the best by far.