Sinclair C5 major consumer organisations published sceptical evaluations. The Automobile Association questioned many of Sinclair's claims in a report published at the start of May. It found that the range of the vehicle was typically only about 10 miles (16 km) rather than the promised by Sinclair, and reported that the C5's battery ran flat after only on a cold day. The C5's running speed was more usually around than the claimed , while its running costs compared unfavourably to that of a petrol-driven Honda PX50 moped. The stability, general roadworthiness, and especially the safety of the C5 were questioned, and the
Clive Sinclair 1,000 a month, placing orders with suppliers for 10,000 of each component to be delivered. Sinclair wrote a book for Bernard's Publishing, "Practical transistor receivers Book 1", which appeared in January 1959. It was re-printed late that year and nine times subsequently. His practical stereo handbook was published in June 1959 and reprinted seven times over 14 years. The last book Sinclair wrote as an employee of Bernard's was "Modern Transistor Circuits for Beginners", published in May 1962. At Bernard Babani he produced 13 constructors' books. In 1961 Sinclair registered Sinclair Radionics Ltd. His original choice, "Sinclair Electronics", was taken;