No, actually, there's nothing about southern England being "wiped out," only (well, not only
) flooded with radiation. Like The Borgified Corpse
says (quibbles about the meaning of "affected" aside), only London is specifically mentioned as being destroyed, which does indeed contradict "Voyage of the Damned." But RTD didn't have a spinoff cast to kill off in mitigating that crisis, so it goes unexplained.