It's beginning to make sense. Different system! Never would have guessed!
Called-up my best friend who is an ex flight instructor and, for the last 15 years or so, a pilot for Delta, and asked him about this. Shocked I say. Shocked. In the US an IFR rating automatically confers a right to fly in IMC, and you don't play the IFR thing unless you hold such a rating. Guess I wasn't as daft as I feared. Just a different way of doing things.
Thanks very much for all the info though...
Dave