There is a perfectly good 100km event on the same day
As I said, the 50 could suit my timings better.
ECE-ing the 50 into a 200 means I'm at home, done by 3.30pm. No trains required as home is 75km from the 'Uts. 75 + 50 + 75 = 200.
ECE-ing the 100 into a 200 means I finish doing 200km at ~5pm somewhere between the 'Uts and home with a £12 train fare plus awkward tube ride to get home (or another 50km to cycle bring it up to 250km and an ~8pm finish).
If, for example, Mrs GB wants to go out that night then an 7pm finish from me is pretty useless. 3.30pm means I can be showered and looking after baby GB well in time. Of course, I could do a DIY ride starting at 5am but that doesn't help support existing calendar entries or give me people to chat to (if only for some of the ride).
Thanks for the clarification on the results page...