In reply to The Potato:
Does it actually have a half power setting or was it cold-blow/hot-blow/off? It looks to me like it's probably wired for that though I suppose one of two heaters could be in series with the motor for warm-blow.
It looks to me like a single pole, double throw switch with a center-off position (or SP3T if easier to find, treat one of the positions as off by wiring nothing to it) switch would do. I think the one you have is double pole for manufacturing simplicity if it actually is at all. Wire the live to the common (usually center terminal) yellow to another, black&blue to the final one. Make sure it's rated to handle 240Vac and the fuse current.
There's not much can go wrong with a switch like that that can't be fixed with a bit of alcohol and emery paper.
edit: just read you have a new switch that isn't working right, seems the blue and black are split for some good reason that's escaping me at the moment. Wire your new switch exactly like the old one and it should work.
jk
Post edited at 09:34