Sergio Perez was handed a five-second penalty and a reprimand for two Safety Car infringements in Sunday’s Singapore Grand Prix, but the Red Bull driver’s win at Marina Bay was upheld by the stewards. Perez was under investigation and summoned to the stewards after the race for failing to maintain 10 car lengths in two separate Safety Car periods, from lap 8 to 10 and then later in the race from lap 36 to 39. In the first instance, it was admitted that while the lights of the safety car were on, Perez failed to keep within 10 car lengths…