In relation to the Deca in Mexico: I'm not sure if the new format of '10 Ironmen in 10 days' is a true ultra challenge. At the end of the day the athlete would go back to the warmth of their hotel room, get a decent night's sleep and have a hearty breakfast before another day in saddle/trainers. The pure and original format of a 24 mile swim, 1120 mile bike and a 262 mile run is on a completely different level.
I have a few ideas. I will stick a pin in it for now but as a taster - who fancies doing a Deca in the UK??