You should be fine. I would recommend taking out the insoles. If the shoe feels comfortable to you just walking around the crib then I wouldn't worry about it. Primeknit stretches out. But, if your toes are bumping directly against the plastic piece in the toebox it might be an issue. If they feel good and you like the way they look then rock em.
Also, the farfetch app isn't working for me right now but they had some sizes earlier at good prices.
Edit - keep in mind, the Kolors didn't come in a US size 8. As with all of the UB Collectives they only did UK 6, 7, 8, 9, etc., so your only choices are US 7.5 or 8.5...