Kitchen has to have a door or window to the outside to be classed as a kitchen.
Its about gas regs and being able to open a vent eg. door or window when you get hot which you will naturally do to stop the build up of Carbon monoxide.
For those wondering, carbon monoxide is given off when a gas cooker is running as there is no flue to the outside.
As Dan says, just remove a couple of items and the problem is solved.