Sinclair C5 computers like the hugely successful ZX81 and ZX Spectrum, an affordable electric vehicle could unleash pent-up demand for a market that did not previously exist. However, Sinclair performed no market research to ascertain whether there was actually a market for his electric vehicle; as the director of the Primary Contact advertising agency commented in January 1985, the project continued all the way to the prototype stage "purely on the convictions of Sir Clive". With Sinclair's new specifications in hand, Ogle worked on a three-wheeled design dubbed the C5, which bore similarities with the earlier three-wheeled Bond Bug – another Ogle
Sinclair Radionics was failing, Clive Sinclair took steps to ensure that he would be able to continue to pursue his commercial goals: in February 1975, he changed the name of Ablesdeal Ltd. (an off-the-shelf company he bought in September 1973, for just such an eventuality) to Westminster Mail Order Ltd.; this was changed to Sinclair Instrument Ltd. in August 1975. Finding it inconvenient to share control after the NEB became involved in Radionics, Sinclair encouraged Chris Curry, who had been working for Radionics since 1966, to leave and get Sinclair Instrument up and running. Sinclair Instrument developed the "Wrist Calculator" to generate