Phew!!! I'm glad that your lens and camera are safe. Good catch!
I like the photos in this post, particularly sized down a bit they look very decent. And usually a 600mm lens is huge and expensive, so for what it is, looks like you've got a good setup to reach 600mm.
The first photo of the kookaburra (with the lighting on it's head) and both kangaroo photos are well composed. Thanks for sharing some of our awesome Aussie fauna on this thread.
My longest lens is my 70-300mm L. While I would love a longer lens, (eg in the 500mm to 600mm area) - I can't justify the cost and weight. As I try to get as close as I can to birds and wildlife, often 300mm is long enough (anyway on my 7D it is equivalent to 480mm in 35mm format, so that's not bad).