The BST changeover happens at 1am on the last Sunday of the Month... if you have a high powered meeting at that precise time... change jobs! :-)
If the person you are having the meeting with hasn't taken in to account the BST change over... DON'T DO BUSINESS WITH THEM! :-D
What we celebrate as Christmas, was originally the ancient pagan festival of mid winter that was held on the winter solstice (shortest day, actually the 22nd of December). It's a Northern Hemisphere thing.
Countries in the Southern hemisphere, do indeed celebrate Christmas in the middle of their summer.
White Christmas is a largely a Victorian idea (Read up about a "Christmas Carol"). During the Victorian period Britain experienced a period of very cold winters where it did snow at Christmas time. Now things have returned to normal it rarely snows at Christmas... and more often than not, it snows in January, if it snows at all. Also check out the Julien/Gregorian calendar switch over to explain the celebration date moving and the change in weather at Christmas :-)
If i wasn't for Charles Dickens the celebration of Christmas would probably have died out in the UK. When Britain became a republic with Oliver Cromwell, the festival was banned, and although it was restored with the restoration of the Monarchy, it was never very popular... Until Dickens of course, only a hundred an 150 years ago or so :-)