Here's another pic I took at the same time as the one below.
I have been fooling around with various camera apps for my G2 Android phone (apart from the stock one that comes with it), and for now I think I have settled on Pro Zoom Camera 5X, which seems to have lots of features, not least of which is that it's auto white balance setting seems more accurate than most. The picture above was taken at the "auto" setting, while the one below was taken using the "cloudy-daylight" one. And now I look at them I think the auto one is actually a more accurate representation of what I was looking at in the twilit woods.
So I think I will try and stick to using Pro Zoom's auto white balance for the pictures I post here unless it looks wildly off (and I'll try and note if I use a different setting).