OK figured it out, thanks girls.
It would have appeared I got duped.
A couple of years ago when they were bringing out the AHR we went into Babies Galore and asked for one. We paid and picked it up out the back. Then drove the 600kms home (not available where we lived) never once assuming they would have sold us the wrong one....now 2 years later I figure it out we only have the MaxiRider II....grrrr will leave her in there a bit longer but S&S have another booster we might investigate if we need one....

eta she's 117cm tall sweetpea.