I've known Iain for years as a friend, and also had the chance to work with him directly on two campaigns for Bacardi and Bombay Sapphire. That combination gives me a pretty full picture of how he operates, and the short version is: he doesn't do anything halfway. On both campaigns, his strategic thinking stood out immediately — he wasn't satisfied with the obvious creative route and kept pushing until the idea actually earned its place. He's deeply tenacious when he believes in a direction, and once he's locked onto something he thinks is right, he commits to it with a single-minded focus that very few people can match. That's exactly what made the work better; he simply wouldn't let a good idea stay half-formed.
Beyond the campaigns, I've seen that same focus show up in everything from his career moves to his training for national-level shot put — it's not a work persona, it's just how he's built. Anyone who gets him on a project is getting someone who will fight for the work until it's actually right.