Looking for a formula to convert American dates to British dates.

*Example is now attached.*

At work, when I export the data from our booking system I'm left with a huge mess to try filter through to fix up so I can use the data effectively.

I've been able to refine the messy data into the same format (MM/DD/YYYY). However, I'm English and the rest of our dates are in British format (DD/MM/YYYY).

I know that there are functions I can use in Excel to overcome this issue with relative easy, however, for certain reasons I'm unable to use these features on this document.

Does anyone have an idea for a forumla that can fix this issue? Even if it's as simple as a formula that just swaps certain characters?

Any and all help is vastly appreciated.