Wow. Completed this the other evening and have to say how chuffed I am. Much more a mental challenge as 20 mind sounds so long and a big step up from previous runs. But Laura helped and i made it. A "tight" calf muscle just after half way threatened to derail me but I wouldn't let it. That hasn't happened since W1 so I wonder if I was going too fast or changed running style? Will give it time to ease before W6 though.