Always puzzles me with Mail across the World near Christmas. It's the same time very year, it's a known fact that there will be extra mail, due to Christmas cards, parcels etc, and, in the UK at least, extra staff are recruited, and additional delivery vans hired. But there's still a longer delay !
And as far as Royal Mail and their money-grabbing, middle and upper class share holders are concerned, they've got a bl**dy cheek to charge what they do, especially for First Class mail, which takes the same amount of time to arrive as Second Class, and often longer!
Second Class - post on Monday, it's normally at its destination by Wednesday, within the mainland UK. First Class, costing twice as much, and supposedly next day delivery (which is what 1st Class used to be!) - post on Monday - it'll arrive when it arrives !!