It was inevitable that the group would split, as suggested in the first post, it was just a matter of when... although it seems it was sooner rather than later.
One of the main problems yesterday was the temperature, my device tells me:
Avg Temperature: 2.9 °C
Min Temperature: 1.0 °C
Max Temperature: 11.0 °C
In the past where I've waited for people to catch up and for me to cycle to a slower pace, rarely happens mind you, this has caused me problems as my core temperature drops... therefore I find it better riding at my own pace in these situations and to keep at a good working temperature.
Problem with this is that it is so windy and cold that there's no shelter to wait for the pack to regroup... but I can see that it could be awful if someone were to drop off the back and have a mechanical.