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 C5 production line remained closed permanently. On 19 September 1985, Sinclair Vehicles changed its name to TPD Limited, with a direct subsidiary named Sinclair Vehicles Sales Limited continuing to sell C5s. TPD only lasted until 15 October, when it was placed into receivership. The receivers announced that 4,500 C5s had been sold by Sinclair Vehicles, with another 4,500 remaining in the company's hands. £7.75 million was reportedly owed to creditors, of which £7 million was owed to Sir Clive Sinclair himself in reflection of his personal investment in the project. Hoover was not among the creditors, as Sinclair had managed to