Of course there will be days when the PER-LHR flight won’t make it due LHR wx requirements. Such was the case when the 744 first starting operating SIN- LHR. Of course the long tour of duty is what makes any diversion more complicated than what SIN- LHR ever was. I’m sure this is no surprise to the boffins beavering away on QCC2 to make a go of this route and as late as Friday last week I was discussing this very issue with some of the 787 team. Such issues have long been a feature of various Qantas routes over the years. I’m sure they’ll remain issues into the future with various other routes as well.