I know Dublin wanted Eurocon and they couldn't have been more happy when London bid for Worldcon. I'm not sure of the exact ins-and-outs of it, but I know the Irish committee discussed using the London Worldcon bid as plus in their favour when plugging their own bid. That happened at last year's Octocon in Dublin. I don't have any indepth background on it, though. maybe it's one of those chicken and egg scenarios?