Driver idling vehicle on corner of Crawford St & Montagu Mansions

I saw the driver idling and asked him politely to turn off the engine while parked up. He told me that the engine stays on all the time and never shuts off all day long. I said, in that case, I would have to report him to Westminster. When I went around the back of the vehicle to photograph the registration, he revved the engine several times, blowing out excessive fumes and oily smoke in my face. That was really unpleasant and unnecessary.