Excel Date Format Cleanup

I have an Excel workbook where every date column is a mess of mixed-up formats. Nothing is missing; the problem is strictly that the existing entries are stored in multiple, incorrect styles. I need each of those values converted and locked into the DD/MM/YYYY format across the entire file.

You’re free to use the method you prefer—formulas, Power Query, a quick VBA routine—so long as the result is a clean sheet that keeps all other data exactly as it is.

Deliverables
• The cleaned workbook with every date shown as DD/MM/YYYY
• A brief note (or commented VBA, if a macro is used) outlining the steps so I can repeat the process on future files, should the need arise