This is illegal in the UK. You cannot legally drive a privately owned scooter in public. They are classed as vehicles and you need to be insured to drive them, you cannot insure a private scooter. When you rent a scooter from one of the apps they come with insurance built in.

Your colleague, and others, breaking the law and driving dangerously does not mean we should get rid of a means of transportation that is legally and safely used by others.