Whilst I totally understand the feeling of "why bother?" in talking to London Information much of the time, I feel it is certainly a good plan to call if your flight is taking you over inhospitable terrain or long stretches of water. Whilst they may not give you much information for 99.99% of your flights, on the day that everything goes suddenly quiet you'll be glad that somebody has some up-to-date information of where to look for you when all you have time for is "MAYDAY, GABCD" before you start swimming!!!
Fly safe!!!