The conversions were completed by H.R. Owen and Crayford Engineering, with bodywork executed by FLM Panelcraft. Crayford's involvement in the project was limited to the interior of the car, and the company had no bearing on the external design of the estate conversion. Nonetheless Crayford badged them as Crayfords for a while (implying that they built them) and only stopped after FLM threatened legal action. Conversions could be carried out at any time in the car's life. Most conversions appear to have been carried out when the cars were 12 months old or older because if a car was converted when new, the conversion would be liable for Purchase Tax like the car itself.