As to the height in the books - yes, it was 2feet in VDT, but I've also been told by my sister that in PC Reep was 1.5 feet.
Now, I'm bad at guessing height, but my first reaction to Reep was that he was too small. Then, when I watched it a second time (having been reading VDT I was trying to figure out if he was 2 feet or not), I thought he was around the right size.
I did think, however, that when he was sitting on Caspian's chest when they first meet that he was too small. It might just be that I have problems guessing heights, but to me in that scene he looked way too small, then in other scenes he looked bigger.
I remember noting that he was about the height of the boy's knees at the end - it was hard to tell as the camera angle kept changing, but when it was about straight on, he seemed to be knee-height to me. Which, to me, was too small as I was thinking 2 feet, but for a foot and a half that seems about right (Unless I'm mucking up guessing heights - this time how high a guy's knee is - again).