I'll try this out, but I suspect that a manual rebuild and using the original files is the best way to be sure of resolving the fundamental problem... the system won't update newer than 1.2.6 and the restore doesn't work properly.
As an example, I downloaded the image folder and manually removed every single cosmetic image as these images were cross-linked to the actual product images. In other words, the thumbnails displayed the correct images but the web view showed some cosmetic products.
I downloaded the new 1.2.8 installation files and searched for every .jpg file before uploading to the web server. It was full of cosmetic product images. I don't know why that, when a new site is created and you specially deselect a sample site, it does not delete all of the images or at least keep them in a separate folder for uploading if a demo site is wanted. I think that a site without samples should be that, devoid of non-utility jpgs.
I even renamed the /system/config.php so I could rename the /images/thumbnails/18 folder and replace it with an uploaded /18 folder set without any cosmetic images to see what would happen. I then renamed the config file back to the original. When viewing the web pages after, it still showed cosmetics and I don't have time to experiment any longer.
Although the original site was developed manually and didn't have a cross linking problem, an imported site does.
There is no need to answer, as if the backup/restore import system doesn't work properly and it's much quicker to just build from scratch.