Page 12, last paragraph
I think there could be a full stop after the first clause of the second sentence.

*** Done

Page 13, second paragraph of 4.4
I found this paragraph a little difficult to follow.  Discussing the higher (lower) metallicity galaxies at the same time as the lower (higher) metallicity galaxies just made it difficult for me to easily parse.  However, I do think it effectively demonstrates the differences in a compact manner.  So while I had trouble parsing it, I don't really have a suggestion for how to improve it. (Helpful I know.)

Overall
one of the largest impressions I was left with after reading the paper was a list of things the paper was not doing.  I think that aspect could be emphasized a little less.

*** You are not the first to suggest this!  I hope it reads a bit more positive now.