Tri / Triathlon / Triathlons - do they float your boat?

Did anyone here take part in the London Duathlon last year? I've been thinking of entering this year as a training target. In theory I think I could "finish" the Ultra distance but definitely not breaking any records on the way... Not competed in one before so interested to know if I stumble across the finish line 6 and a half hours whether I'll be firmly last?

EDIT: Just saw last year's times and "yes" is the answer. I'll give the Challenge distance a go instead.