Well following this thread, and diotalevis comment I did a little research into the flyweight pattern.
Thanks for the info! It's been so long since I read TheDamian's book I'd completely forgotten this. (You've also made me realise that somebody has nicked my copy since it's not on my bookshelf... grrr... darn sneaky coworkers...).
Fortunately the relevant chapter is online.
Its possible (and I think likely) that the concepts were originally the same, but I suspect the design pattern movement redefined and extended the concept from its earlier use.
It looks like it was the other way around. TheDamian references Design Patterns in his book.
Personally, I don't think the technique described is an instance of a flyweight pattern, since we're taking not taking the state information from the class, just rearranging its location within the class.
The whole point of using flyweights is to cut down on the number of objects you create by removing the context-dependant information from the class. The context specific state being passed to the flyweight objects as and when necessary by its client objects.
TheDamian's technique might use some of the same stratagies as flyweights, but with a different intent.