I have decided to go for the packaging design below as I agree with the feedback I got and it is the layout that uses the space the most successfully and it does look very modernist. However, I am going to make the tweaks suggested and use the grid more. Below is both the altered packaging and the grid I used. It's a lot more successful as it is consistent and flows really well, and I think it will flow when around a bottle too. I want to see what it looks like prior to printing to make sure it is perfect, so I am going to mock it up using Photoshop.