By Sarah Young LONDON (Reuters) -Britain's biggest car maker Jaguar Land Rover (JLR) is extending the closure of its factories until October 1 following a cyberattack in early September which has left its operations paralysed and smaller suppliers struggling. The luxury carmaker, owned by India's Tata Motors, has three factories in Britain which produce about 1,000 cars per day. The group is said to be losing tens of millions of pounds, with many of its 33,000 staff told to stay at home. British busi ...