Cornish confusion?

Our first Christmas card arrived today, posted yesterday in Cornwall where St Andrews Day celebrations clearly begin on 29th! Or is the Cornish post the most reliable in the U.K.? Perhaps the Celtic connection is the reason. We had our local grandchildren with us today and we went to a small farmyard where we bought our Christmas tree. The boys helped us take it into the garden until it’s time to bring it inside for the festivities!