😱 Wow, that looks really bad, I would have to remove it because it would drive me mad every time I looked at it. I fitted a BSE, took my time installing it and making sure it was perfectly aligned and it turned out brilliant.
I understand Invisible Shield offers a lifetime warranty, I would suggest you send them copies of these images and explain that it was fitted by a supplier and they may replace it for you.
My understanding is that the BSE and the Invisible shield are identical or at least very similar products and I'm pretty sure that if you tried fitting it yourself you could do a better job than that.