However, Glenleven waited until after "the period of mourning retirement … was at an end". It seems unlikely that Ailsa's formal mourning lasted less than a couple of months—indeed, a year would be more seemly. And Glenleven's attentiveness must then have extended at least a further month or two. So I've placed the duel relatively early in the permissible range, hoping to be off by no more than a month one way or the other.