>>13742193
Okay, this is just an exercise. I brought up LONDON as the base location for a night sky simulation on TimeandDate. I used Christmas Day and am facing Northwest. How can you tell the brightest star? Watch which one appears first at twilight? Good guess.
I get VEGA popping out at twilight in the Norrhwest. See caps. It is the most prominent star, in that direction, and from twilight until 10pm closing. We are just thinking out loud here. Spitballing. But anons can see what is being contemplated.
My feel for the WinterWonderland timing is that it is in the early part of the evening . Well duh, right? If you know the venue will be closing at 10, what time would you arrive? Think for yourself. Just there for a secret hand-off of secret stuff? Or maybe combine a little fun since you are here in London?
As for the ROT1 pic, if we follow the open source markers: Millbank, SE tower scaffolds, North tower shroud, it seems pretty close to Christmas Day. But what astronomy sites tell us about when the Moon would be seen in London on Dec.25, 2013 is that the ROT1/EMB set represents a very late portion of the evening, as the Moon rises at 12:44am.