That has work Peter......thanks for the suggestion...CheersThe attached workbook explores Excel formatting to switch between languages.
The validation lists are date-values with explicit language settings.
The table headings are also date-values but conditionally formatted, as is the user input cell.
The key is the use of the last day of the month irrespective of language so the searches on number are independent of language settings. It may be that a correctly set up workbook would respond to the Windows localisation and this user interaction is unnecessary. I have no way of testing that however.