Iridiums are good fun Ice.
"The Intensity (mag), is that the intensity at it's brightest, or at it's dullest?" Brightest at the peak of the flare.
"How does it compare to the "Intensity at Flare Centre (Mag) in the 2nd last column?" eg The 3rd column on the 18th Nov is -0 your location. The 2nd last column is -8 at flares center location. It's brighter at the flares center location.
"Does the one on 19th Nov mean it's not going to change brightness at all?" No it will change, but it peaks at -8 much brighter than the 18 nov -0 flare.
"Does the one on 18th Nov mean it'll start out at -0 and get as bright as -8 before disappearing?" no -0 is the peak at your location, you would have to be at the flares center location to see that one at -8.
"What does the distance to flare centre mean? How far it travels across the sky?" No, not the flare. It's the distance and direction you have to travel on the earth to see it at it's brightest.
"For the Azimuth direction, is that the direction it's coming FROM or going TO? If it's the direction it's coming from, how do you know which direction it's going to? And vice versa." It's the location of the peak in the flare. They don't tell you which direction it is coming from or going to. Most of the ones I have seen travel from North South, I think they are in Polar Orbit
http://tinyurl.com/4xnsf I've never seen one East West
Mick.