However, that said, looking at the website...
Half of what it says is Art Moderne, I'd have said was Deco.
Maybe in the UK we see both styles and just lump them together as Deco.
Here the sweeping curves, that it has in its Art Moderne page, would certainly be called Deco.
That said, one lead on from the other, so they could just have been lumped together in our defintions :-)