[3] It featured ice chests in the sides through which coolant ran and a telescopic sight on the cowl to help avoid running diagonally.

The Rootes brothers, friends of Segrave and Irving, provided the Irving-designed individual aluminium body panels from Thrupp & Maberly.

[4] Irving had left Sunbeam and his new employers, Humfrey-Sandberg, granted him permission to use part of his time designing and constructing Golden Arrow for ex-Sunbeam driver Henry Segrave.

An irreducible minimum was arrived at for the size of the cockpit because it had to be large enough for a sixteen-inch steering wheel believed to be needed to give sufficient leverage.

The whole shell was shaped to exert a downward air pressure to keep the driving wheels on the ground and assist stability but a further 260 lb (120 kg) of lead ballast was added to the tail.

[5] Segrave found he could not use all the throttle opening until past 2400 rpm, or, in bottom gear, until the car was moving in excess of 55 mph (89 km/h).

[5] Irving was helped by chief draughtsman W Snell, his brother lent by Alvis to supervise the car's building and his daughter who dealt with all the associated progress-chasing and administrative work.