You guys are not unique! I had a letter posted to me from York on December 16: that's about 220miles away at most. It arrived in the first mail delivery we had that week on Jan 16. In the same delivery was a Christmas card form New Zealand posted on Dec 15 and another card from San Jose CA, posted on Dec 19.
Admittedly, my local sorting office was closed for two days for deep cleaning for CV19, but still....even with 35% of staff in isolation, one would have hoped for better. Or at least a special refund stamp! Plus a letter form the hospital making an appointment for me arrived the day after the appointment - 13 days after posting!
Time was in the mid 1800s when there were three mail deliveries per day and two on Sundays….