They call Sabastian Sawe the silent assassin. And, whisper it, but the Kenyan may just take down the men’s world marathon record in London on Sunday. It is an imposing target, set by Kelvin Kiptum in 2023, which stands at two hours and 35 seconds. But Sawe believes he is in similar shape to when he went for the world record in Berlin last September, only to be thwarted by temperatures in the mid-20s centigrade. Intriguingly, this time he also comes armed with Adidas’s new Pro Evo 3 supershoe, which weighs in at an astonishingly light 96 grams, and he says is even faster than its predecessor. Asked on Friday whether it could lead to him breaking Kiptum’s London course record of 2:01:25 or maybe his world record, Sawe gave a short and partly instructive answer: “Yes,” he said, to laughter.…