I have used TestDisk and Photorec a few times before, and found them to be very useful for corrupted drives, etc. However, this time the drive is physically damaged (portable drive that was stood up, got knocked over). I used dd_rescue to image the disk and have been trying to run TestDisk on the disk image.

It's a 2TB Segate drive, that a friend uses for her photography scratchspace. There was about 300GB of used disk, the rest is empty. This was echoed by dd_rescue. Photorec was able to recover 1000s of pictures, raws, PDFs, etc from the disk image, but it would be very helpful if I could get the NTFS filesystem up and running again, so here I am.
After the quick search, TestDisk says "The harddisk (2000 GB / 1863 GiB) seems too small!"

I am now running a deeper search, but the last time I did, it didn't find anything. The person I am helping isn't very IT savvy, and I expect the disk was as provided by the retailer, formatted NTFS 1 partition for the entire disk.
If someone who knows more about this stuff could point me in the right direction, that would be greatly appreciated. I'm competent with Linux and computers, just not with filesystems. I'm out of ideas here. The output of Photorec is good enough (as minimal data is lost), but sorting the data will take ages - it's worth me trying to recover the filesystem.
I found a similar question 'Help - Drive too small / partition ends after disk limits', but the deeper search fixed the issue. For me, I don't think it will (tried before, but didn't find anything, then went on holiday and PC was turned off).
Any help is very much appreciated.
With kind regards;
George M1GEO.com