It seems to be a common problem that Excel doesn't pick up leading zeros which is important for phone numbers, bank accounts etc. This is because it forces the conversion of text fields into number fields on import. Even when I try to format the cell back to a 'Text' field the the leading zeros don't appear.

I vote that we have a tickbox to Force text fields on selected columns or for the entire CSV export. This can be done by containing the field with commas and an equal sign. ="00123".