Automate Excel Date Formatting

I have a worksheet where all the dates are produced by an existing formula-driven script. At the moment the resulting numbers appear either as raw serials or in inconsistent layouts, and I need every one of them to display consistently in DD/MM/YYYY format—no manual touching of cells once the sheet recalculates.

Your task is to adjust or extend the current formula / VBA / Power Query approach (whichever is simplest) so that each time the numbers are regenerated they are recognised as proper Excel dates and immediately shown as 31/12/2024-style entries. Nothing should break the existing logic that supplies the numbers; I only want the presentation layer fixed.

Please deliver a working file or clear code snippet with a brief note explaining where to paste it, plus a quick test to prove the formatting holds after recalculation.