English Jon:

The point I was making is that any duet is harder to play than Northumbrian pipes - essentially because the pipes play a single note "line" whereas a duet is playing multiple parts.

As I understand it, the "actions" involved with playing uilliean pipes make them rather a different matter.

And clearly the distinction I made is only really an issue for those starting off on an instrument; mastery of any instrument is a very different matter, and the sort of comparison I was making becomes irrelevent.

G.