Thank you very much for the additional information.
It's definitely very odd that the problem has only been seen in your own galleries in Mobile Safari on your own iPad.
The difference may be because I am using my index.html file to host a great many links to individual Galleries?
This should really not make any difference at all (and I can't actually see how it could make a difference).
However, as you are already aware, until we know what is causing the problem, we can't rule anything out.
I use iPower to host my Site and I am fairly sure that they don’t do anything strange which might affect the way that their Server delivers content to the Internet.
I agree. I do not think that your server is part of the problem. A Juicebox gallery really does not have much in the way of server requirements. A Juicebox gallery is basically just a collection of HTML, CSS and JavaScript files with a few other resource files (font and image files) and pretty much any regular web server should be able to handle this. (Only the Download Button and Password Protection require further requirements: PHP 5.2.0 or later.)
The icons in a Juicebox gallery are characters in a custom font. If there was a problem with the font files, then I'd expect all the icons (not just the Back Button) to be showing up as an 'X'.
As I was never able to see the problem for myself (even on my own iPad) and as the Back Button displays correctly when centered, I think we can definitely rule out corrupt font files as a possible cause.
I would still like to see the problem for myself (even if I can't experience it) so, if possible, please post a screenshot of the mysterious 'X'.
Maybe it's a really rare bug which just manifests itself in one particular browser on one particular device under a certain combination of gallery configuration options. It seems unlikely but not impossible.
I have uploaded a test gallery using exactly the same configuration options that you do (and the same version of Juicebox). I've copied the configuration options from your Hummingbirds gallery which still has the Back Button to the left. The only thing I've changed are the images so you'll not see an image on the Splash Page but the Back Button should display correctly and redirect to your site index.
Please take a look at this gallery and let me know if you see the Back Button or an 'X'. Thank you. (I'll take the gallery down after you've seen it.)
[Test gallery removed.]