I'm looking to buy a karambit, I found a sharp one on Ali express and the blade is over 3inches making it illegal, however I see reviews for people in England who have bought it. (All 5 star) (Had over 1K orders and each review has a wide time gap so I doubt it's bots)

So I check at a more official site (Elemental knives uk) I get the karambit sizes and the blade is also over 3 inches.

So is it ok to have a blade over 3inchs if you order it? or are you just not allowed to bring it out on public property?

This whole law is very confusing to me and my thanks goes to anyone who can explain this for me.