I recently figured out and notated the bass part for "Mean Mr. Mustard." I don't really have much to say about it, but I'd like to draw attention to how - apparently without reason - it changes from 4/4 to 3/4 at the end. I hadn't noticed that until I notated it.
I think there's a drum bit at the beginning, so the song actually starts with an up-beat, but I didn't include that in my notation; I just started it when the bass starts. As always, there's the disclaimer that I might have something wrong (especially the notes in the last measure, which were a bit difficult to distinguish because the track break between "Mean Mr. Mustard" and "Polythene Pam" falls in between those last two measures).