By Keir Mudie Peter Mandelson reckons: “We are now in the long campaign for the general election. And it’s going to be a tough, endless, rollercoaster ride.” Quite. That was just after news about problems in Rochdale began to break and Labour started to come under some pressure. He added: “That’s what hotly contested elections are like so everyone better get strapped in for the ride.” Never really associated Mandy with white-knuckle rides, saw him more as a ghost train man, but goes to show you never know. Anyways, it was quite the week for Labour but I’m not sure it was as up and down as the …