UK was 10 degrees warmer than the rest of the countries I visited but had worse weather damage, potholes, on the roads than these other countries.
Cycling in the winter can be comfortable, interesting and rewarding but its a bit slower and lonely compared to the summer.
St Pancras is the best station I passed through, its beautiful, has excellent facilities, nice places to sit and is easy to use. Bromley South station had the most helpful rail information, (companies please note an informed person is at least 10 times as effective as a website). Deutche Bundesbahn has great conductors, if you like cycle touring go to Denmark.
Sweden has the most comfortable sleepers of those I used. Eurostar has the best luggage provision.