Yeah Gillian, I'm barely able to read some posts a day most of them related to music which by other hand, you know, asks me for more practicing time...
About the data issue, nothing to be added, you created a data partition that is a really great practice regarding backup stuff. They simply did it totally wrong.
Life goes on so another ítem for the list, reordering your shots. Fortunately you made cloud backups wich is very convenient.
A matter of time and effort now...