A little piece of added pedantry. Dawn in London around Christmas comes at a little after 8am. But, between 1940 & 1945, British clocks were on GMT+1 in the winter, +2 in the summer (the idea being to make better use of what little daylight there was). So if they want to farewell Caspian in the back garden at dawn, it's going to be about 9 in the morning. I hope they have high fences!