(Reuters) – Britain’s multiple world and Olympic long distance champion Mo Farah will run a marathon for the first time since 2019 when he takes part at the London Marathon in October. Organisers said Farah will return to the roads and race in his hometown marathon on Oct. 2. “It does seem a long time ago since I last took part in the full race in 2019 and I can’t wait to get back out there again,” said Farah, who finished third in the 2018 London Marathon. Farah, 39, will prepare for the marathon by running “The Big Half”, a road running competition over the half marathon distance, in Septemb…