No one who wants to stab someone is doing that.
Chefs can carry knives. Legally. Big ones, not little ones. They could stab someone. Plenty of chefs are alcoholic either anger problems.
You could be moving to a flat down the street and carry a box of kitchen utensils, you’d be legally carrying a knife. You can then stab someone.
Going to a friends to help with dinner, just bought one from John Lewis, Wiccan going to a ritual gathering, literally any reason that is “oh, I’m going to this thing and need the knife for that, but it’s wrapped and in a bag.” And they could, if they chose, stab someone.
These things don’t happen. Because the people who want to stab someone are carrying concealed weapons illegally with the intent purpose of being able to stab someone. They don’t come up with excuses to carry it. I’m sure it’s about 50/51% of knife crime is committed with a normal kitchen knife - which aren’t being carried for traditional or religious reasons, nor are they being carried by a chef or similar. They are being carried illegally.
Closing these exemptions will have no effect on knife crime. It is a knee jerk reaction.
Knife crime campaigners have been trying for years to have pointed kitchen knives phased out, other than for professional use, and make it so you can only buy curved tip or flat tipped kitchen knives as they cannot easily pierce skin or clothing, and would be much less of a threat in spur of the moment “grab a knife” crimes and they would be less attractive to carry around without the sharp point. Are you joining that campaign? The one that really would make a difference? There is the brand Viners Assure who have started making those, and who are trying to help push safer kitchen knives which would be less use in knife crime as it is now. Do you own those?