I've hit a few problems using PhotoRec. The first being that when selecting what files I want to look for there is no option for .avi or .mkv which seems a little odd. Secondly I can't choose anyone to restore them to other than Ubuntu which doesn't have enough space. Also, seeing as it's unwise to recover them to the drive they were lost from, I don't have room to recover the whole 600gb, so I want to choose around 300gb to recover which doesn't seem possible.