Summary

With tsiridan excellent design, I was having issues with the fingers of the latch snapping at their base when I tried to fit the latch to the UPS and when pushing the pin through (in either PLA or PETG).

Thanks to tsiridan uploading the freecad file, I was able to change the latch to instead of four fingers, only having three, giving more area for the base of the fingers where they were snapping for me.

I also sliced this at 95% size and then drilled out the centre hole with a 5mm drill bit until it fit the pin snuggly.