Mixture of date formats

[heytherejem]

I have a spreadsheet with a date column.

In that column, are dates which are both in dd/mm/yyyy and mm/dd/yyyy. Excel believes them all to be dd/mm/yyyy so I can't simply convert them all.

I wonder, besides manually looking for and changing the US dates into UK dates, is there anything I can do?

I have attached sample data - i've highlighted the incorrect dates in red for the first few. The only way I know they're wrong, is because they should generally be in chronological order, and also many of them are showing as future dates.

[Special-K]

"they should generally be in chronological order"
in G3
=IF(D3<D2,1,"")

"and also many of them are showing as future dates."
in H3
=IF(D3>TODAY(),1,"")

copy these formulas down the column

Where there may be problems a 1 will appear in the column.
Editing this manually shouldnt take you more than 15 minutes.
You only have 600 and within a minute I'd worked down to the first one hundred.