I ordered a pair of shoes UK size 7 EUR size 41, and the shoes I received were EUR size 40.5.
I complained that the EUR size was incorrect on their website, and they told me that it was only advisory, and not reliable.
But nowhere in their terms and conditions it is written that the EUR size is advisory.
Anyway, they refused to acknowledge their mistake.
So, the lesson is to not trust their EUR size, and check it elsewhere before ordering.