I will check this, however, if the permissions are the issue stopping Simple Image Gallery Pro from displaying correctly on some pages. The pages correctly displaying a gallery should display a blank space like the pages I provided links for.  Is there anything else that might be  causing this issue?

I can't think of anything else. You should try uploading images through media manager to every folder you have galleries and see when you can and when you can't. To those you can't the problem is the owner's permissions and under which owner the folder or files are created. All files and folders should be under the same owner otherwise just make those folders permissions 777 and check what happens then.

My hosting provider has checked the permissions and I'm able to upload files via Media Manager, however, Simple Gallery Pro is not displaying consistently across chosen pages, even after I have deleted previous folders and recreated with new names etc...

Now working again.  Quite strange I know. 

Thank you.

Desw