https://kufiya.org/
There's an auto-queue and at the time of writing this there's like 3600 people in it (and an estimated like hour wait), so no guarantee of anything being in stock by the time you read this; but I figured I'd post this in case anyone was waiting on them to restock. 
PSA: For people who are disappointed that things are out of stock, or do not want to wait in line in front of computer for hours during in-stock factory sale, you can preorder all Hirbawi designs (essentially, made-to-order) via abuwear - this is Hirbawi's licensed distribution in the UK. Abuwear only takes $5 markup compared to direct order via kufiya.org
https://abuwear.com/pages/hirbawi-kufiya-pre-order-policy