I think royal mail has a backlog of parcels as well, I made an order from another shop 20th of November 2020, and I assumed the parcel got lost, so I had to refund and reorder later.
Now checking tracking today on my second order, it is in the UK, and I thought I would check the tracking number on the lost order; and it was out for delivery today, but I think now It will come tomorrow, lol