I live in the Netherlands, and have glass on glass 2 different online stores purchased.
For all 2 stores I was very satisfied, the glass was exactly on the agreed day and time comes.
With these online stores had the glass also slightly cheaper than normal shops.
I can post the addresses do but I do not think you have much outside the Netherlands.
Moreover, I have most of the materials bought at online shops.
In the Netherlands, you have good internet store labels.
In this type of stores you can generally safe buy stuff.