The fate of chassis 004 remains something of a mystery, as other than the gap in numbers there's little evidence of its existence.

One suggestion is that it was the car destroyed by Jamie Davies at Snetterton. Davies had been drafted into the works team as a temporary replacement for Kelvin Burt who was unable to race following a big accident at Oulton Park which destroyed chassis 006. However Davies himself had a big crash during pre-event testing and had to be cut from the car.