Turner used Smiths instruments for their cars, apart from the Ammeter which was a Lucas item. It is quite remarkable that Turner as a small company was able to convince Smiths to manufacture special versions of their speedometer and tachometer for Turner. These two instruments are coded SN 4103/xx (120 mph max) and the mechanical RN2309/xx (8000 rpm max) and very rare.
The information below is taken from a Smiths “Equipment Schedule” for Turner Sports Cars dated June 1962. It comprises all Smiths parts for the various Turner cars from approx. 1959 onwards. Some items are not exactly clear like e.g. there is only one ratio used for the Speedometers, whereas cars had 13” wheels or 15” wheels.