esmi - I had been apparently pushed off onto a pending approval basis to post on the theme's dedicated forum - I assumed then it would be quicker to post here - as indeed it has proved.
Thanks for coming back Sayontan. If you tried it last few minutes I was looking at the new 2013 theme so it may have been in in an inappropriate state. Well interesting because before I lost the header in the first place I tried to set the Header in there - forgetting as it has been a while that Suffusion had its own implementtion.
I uploaded via the Appearance / Header interface only to find it tiled the image. At that point I remembered Suffusion has its own. So I removed the image that was newly set there, and proceeded to use Suffusion to effect the change instead.
Can I do it in both interfaces? - well if I do it in the Appearance / Header interface the image loads but I can see no effect with changing from default to Custom Styles in Suffusion. i.e the former is taking precedence.
But that method is still tiling vertically beneath the menu bar, I will leave it there now if you want to look, but although it is not easy to see because of the nature of the image, the bottom row of freight containers is actually a repeat of the top row of freight containers.