The most recent that falls within the scope of the sub's rules is probably the Battle of Mount Tumbledown during the Falkland Islands Conflict.

A combined force of Scots Guards and Ghurkas charged a well-defended Argentinian position on top of Mt Tumbledown, which overlooked the town of Stanley. The charge occurred at night, and managed to carry the objective at relatively low cost to the attackers.

Of course, there were plenty of bayonet (or sword) charges during the Pacific War, and there have been some recently in Afghanistan, but those are within the 25-year rule.