[BUG] - Example files need to be corrected on main and 0.4 release

[kd-ods]

Summary of the bug or issue

We effectively hand-rolled the example data for the 0.4 release. Unsurprisingly, the use of the example files for testing the updates to the Data Review Tool and the Visualiser uncovered various issues with the data.

Suggested resolution

We should correct the example files. Once the tools are released we can do final tests on the corrected example files, merge into main, and then replicate on the release branch.

[kd-ods]

Going to leave this open until we've updated the 0.4 branch in the new year.