I managed to pick up a copy of Duell, the fencing card game, which is a republishing by Ravensburger of En Garde by Reiner Knizia, from eBay. Having read the various comments on BoardGameGeek I used the En Garde rules and tried a few games with my wife, starting with the Basic Game and moving on up through the Standard Game to the Advanced rules.
The game is very simple in concept a linear track is placed between the players and pawns placed on either end of it to represent the fencers. Each player is dealt 5 cards from a deck of 25 (5 sets of values 1 to 5) and then plays the cards in turn to advance down or retreat back up the track or to attack their opponent. With the advanced rules, which include advance and attack and defensive retreats it is a really fun game that actually manages to give the feel of fencing despite its simplicity.
The production values of the Ravensburger version are fine but if you are looking for a real visual feast you might want to check out the version of En Garde being produced by Ferti (although it doesn't contain the English rules so you'd need to download those). Personally if I want to improve the look I'm going to fish out my Redoubt Musketeer figures and I'd also like to work out a way to get it into a miniatures game as it's the best fencing simulation I've found so far.