Swap date formatted as MM/DD/YYYY to DD/MM/YYYY without converting

I am trying to import some data from google my.maps into excel for analysis.

I have "date visited" as a custom field which I enter in to the map over time. I want to export the map data to look at this field specifically.

When I export the data from google it appears that it automatically reformats this data to MM/DD/YYYY and then to MMM-YY. I am in the UK and adding dates as DD/MM/YY so this is intensely frustrating.

I would like to "invert" the date fields to get the correct date out.

The date is in a mixed column with many other integer values so I can't simply convert the column to text and then to DD/MM/YYYY.

To complicate further, dates with the first value above 12 (eg 17/02/15) are stored as text strings.

Sample data: http://ift.tt/18uBQGR xlsx