1. How do I position the Slider in the centre of the header?
a: put a table in the header, 100% x 100% and then right click in it and choose cell options
set it to center and middle, then put the slider in there
2. The images are not behaving as they should and seem to be loading outside of the "container" to the right and then settling back within the container.
How do I correct this?
a: Not 100% sure but I think if you set the slider to overflow: hidden; that may work
3. Then I can't seem to get the horizontal Navigation Menu to line up in the grey infobar. How do I fix that?
a: that is a padding issue, set your info bar to 0px padding, if you need to then adjust it add 1 at a time
or adjust the menu properties not sure with that particular style but play with it and it will come right
4. Then there is a large white space that sits between the Left Sidebar and the text in the Main Panel which I can't seem to reduce. How do I fix this?
look at the image you have spacing and alignment issues, that are easily fixed
hope that helps