The question is how to callibrate for Sky HD and the problem is the same as how to callibrate for Sky SD.
As there are no test patterns broadcast (afaik) for either platform you can only guess or approximate. Tarbat, using a 1080i output from a PC is doing an approximation but this misses a point as video black is set differently in HD to SD, so simply sending HD resolutions does not overcome the problem, unless you use HD video test patterns.
What we really need is good old test patterns to be broadcast so we can use these to set our displays.