Have bought an Obaby Zezu pramette/travel system and there seems to be some 'play' or movement when the pramette or car seat is attached to the chassis. Is this usual? It's not excessive and not noticeable when either are in use with the chassis, but there's definitely a slight wobble when the pramette is touched. Also, the pramette does not lie completely flat when attached to the chassis, it dips down ever so slightly at the feet end (probably barely noticeable). Is this normal? Or is the pramette unit supposed to be totally flat? Anyone else noticed or experienced these issues? Any relevant comments regarding these questions or travel system would be appreciated. Thanks!