To be honest, this is the conclusion I'd come to, until I found the census record for 63 Methuen Street Liverpool of 1911 which refers to them having been five years married.
From my experience the census error rate, either by enumerators at the time or indexers in the last few years, runs at about 20 per cent, so I wouldn't take the five years figure as a truth set in stone. The family appear variously as Cockram, Cockran, Cockrance and Cochran in the various censuses from 1881 to 1911, which just helps to make life a little more, ahem, interesting.