In the aftermath of the ash I did Frankfurt Hbf > St Pancras in 7 hours. I caught a very late running ICE from Frankfurt to Brussels and Eurostar from Brussels.
Given the general chaos and overcrowding it wasn't too bad an experience.
Eurostar told me that the train was overbooked and they couldn't guarantee me a seat. When I got on the train at Brussels, the train manager invited me to choose my seat as there was lots of free space! Grrh!