Cheers.
Here's the other thing I've been playing with this evening.... this is 9 shots in one image. The bottom layer has zero opacity. The others are layered over it, running 20% opacity, except the top layer which is at 50%:

H'mmm, now which one.
Both first and second were taken on a drive home tonight specifically for this comp. I actually wanted to put in a piece of video, but figured as it's photography it'd be excluded. Annoyingly I had a couple of evenings that were clear as a bell when I could have shot it...... but the C's not all there yet, so it would have ruined it.
The 500D was on self-timer on a mount, on the window, with the 10-20mm, no flash and a 1/250 exposure. They were shot in RAW at 17:40hrs for the first and then about 17:55hrs for the composite and then I've pumped the brightness, pulled the vibrance back a lot and slightly pushed the saturation.