"Canne de combat." Which the Milliways translation may or may not translate as singlestick, unless of course Harry is hearing this whole conversation in French anyway.

"Yes, whenever thou likest -- dost thou have one?"

Easily gotten from Bar, if not.

Also, you know, practice padding is an option, but they may not need it for the first lesson or two anyway, depending on how different it is from what Harry knows.