All good things must come to and end, and that also goes for the M3, of course. Whether you consider Southampton a happy end is another matter.
If I have to single out one thing about jazz that I am not too keen on, it is probably the chaotic endings that seem to be par for the course. To me they indicate a lack of imagination, or an unrehearsed gig. The ending is part of the tune, and it ought to fit in style and mood.
Here are a couple of selected endings from my recordings. The tunes are all available in full versions elsewhere on this site.
The end of Contemplation (mp3) runs through the three chords the tune is based on. The final chord is not entirely clean, it has a slight edge to it.
The end of Turnaround (mp3), on the other hand, is very clean.
The end of Hey Jude (mp3) is similar to its intro, which incidentally is a theme that appears only in the middle of the original. It is sometimes nice to 'bracket' a tune in this way.
The end of Autumn Leaves (mp3) is set up by a fast run made up for the occasion.
The end of The Chicken (mp3) is also set up by a single-note run followed by a chromatic progression of dominant chords. A half-step slide from one dominant chord to another is very often used in funk music.