After posting the previous post I went back and compared the looks a few times and realised I was a bit harsh on the ARRI LUT, considering that it was very flattering on my battered skin tone but basically didn't screw up the strong colours too much, whereas the film look is much stronger without being that much more flattering.
Inspired by the ARRI LUT, I created this custom grade from scratch.
SOOC (for reference):
New Custom Look:
ARRI LUT (for reference):
I'm actually really happy with that look - I went a bit further in evening out the skin tones and brightening them up a bit and it didn't seem to come at the expense of anything else.
I think I could easily build a look around this, and will experiment further.