Wish, how exciting! Of course you need to go to DLR, not going isn't an option!
As others have said here - there are a plethora of trains you could take. But me personally, I prefer air. Commuter flights in Europe can be really inexpensive. I flew return from London to Nice when I was in Europe in June, and it was less than $150. The train ticket was actually a little less expensive, but not by much, and in some case I've been told the train can be more expensive than a flight by far.
It's not a question of if, but a question of how :-)