Big date anomaly

Afternoon,

I have some dates in a spreadsheet and I want to do an =month() to get just the month back for a tidy pivot.
However - if you open the attached document, excel is not recognising the date. I tested two date columns, both aren't working.
I tried ensuring my dates are in UK format (dd/mm/yyyy) and also data-text to columns - DMY. Neither have worked.

I'm stuck!

Thanks in advance :-)

Jemma

Thanks once again, Glenn! So simple, i'll have to remember that one! :-)