What, of December? No, if anything the Post Office is busier than ever in December, delivering Christmas cards (though not as many as when I was a kid). The only Saturdays the Post Office does not operate are if they happen to be Christmas Day, Boxing Day, or New Years Day (or presumably also January 2nd in Scotland).
only when the date falls as near, the holiday,
if unsure the postal as the area as you should provide.
...the second Saturday of what? The month? The year? Lent?
Your question makes little sense.
