The tempo choices of recent recordings are very adequate - the pioneers of period instrument playing tended to choose tempos as told by 20th century teachings, but research has shown the palette of tempos was much wider, and some were indeed fast and furious. Couperin had a virtuoso side to his playing, too.
This is also supported by research on the titles of Couperin pieces and the meanings and persons they refer to:
amazon link - see also on Jane Clark's site janiculum
Yes, I know, and I wasn't referring to the choice of tempi; what I meant was that the sound tended to be congested in the fast pieces on that particular recording, as if her trying to get somewhere in a hurry (hence the Paddington remark) was making the sound muddy and opaque. I don't know if the instrument is to "blame" or if it's an engineering thing, but I didn't like what I heard, at least not in the faster pieces; I didn't like the piece where Hantaï joins in at all.