Copy Only in Excel on OneDrive

I want to share a "lookup" Excel sheet in OneDrive with staff, which allows staff to only copy the data in the cells but not to edit or delete it, without them having to download a copy of the sheet and then copy the data. I've found a solution to add data validation, but it unfortunately doesn't work on all the cells, even though data validation is turned on for the cell. For example I could delete A6. File also contains hidden sheet. Solutions will be welcomed.

The warning message was just a "nice to have", it's the looking up of the list on the hidden sheet, I hoped would prevent them from changing the data, but it doesn't seem to always work. Locking the cells doesn't give staff the option to highlight the data in the cells and then copy it over. The data in my mock-up sheet is probably too simple - my real data, has a much longer string and it's important to be kept in the format eg. no spelling errors or spaces added (to allow the import of data).

Thanks Ali, I've tested it again and it worked - was the whole time trying to insert the cursor at the formula bar to highlight and copy it but it worked just by copying the whole cell