Sorry to disagree Mark, but any date using numbers only has the potential to be ambiguous.
A date wriiten as 1945-06-08 is ambiguous! Did the writer mean 8th June or 6th August?. Was he using your unambigouos format? Just looking at they date one cannot tell!
The only way to get rid of ambiguity is to use month names rather than numbers.
This is particularly true with old ‘Julian’ calendars, where years began with March as month 1. If the parish register used month numbers rathan names, it is easy to get caught out. So a baptism taking place on 1st day of Month 12, actually took place on 1st February (the following year)