I thought it was a test of intellectual potential and attainment, not stamina!
I really do take your point, but I still can't help feeling that it's not the most grown up way to behave. I'd add that I know for a fact that St D's exam 2 years ago was about 10 days earlier (I hadn't appreciated that last yr was the same as this year, as you mentioned above). So as far as I'm concerned this is a conflict created by St D, not by Alleyn's trying to test them when physically and emotionally drained.
Our son wants to go to Alleyn's most of all, but regards St D as a very acceptable reserve choice. So he doesn't want his first choice impacted by possibly being tired from the St D test the day before. I've heard it's done very well too, but it is a full day of exams. We are genuinely considering just going for Alleyn's, out of the two. Colfe's is the Friday before.
I also can't help noticing that Alleyn's isn't back to back with any of the other foundation schools (Dulwich and JAGS) - no coincidence I'm sure.
anyway, thanks for the encouragement, much appreciated.