ok, so update to this, I got the Viz US Blu-Rays Set 1 and 2 and checked to see if the errors are present, the results were very surprising
apparently the UK version is a copy of the AU Hanabee version, so this applies for both, but I'll refer to it as the UK MVM version as that's the one I have and speak for both
1. the visual glitch in a couple frames in ep 24 is not present in the US Viz version
2. the sub file error in ep 13 is not present in the US Viz version
3. the audio is way higher quality and louder in the US Viz release
4. on average, episodes are 1 GB bigger in the Viz US version than UK MVM
so this is nice and well, all my complaints resolved, but I was shocked to discover the DRASTIC difference in colors in some areas, the Viz US version is so much better, I can't even believe how they made it look so bad in the UK MVM version, it's day and night, examples in the IMGUR album