From what I've read on-line (regarding guidance about guided reading), 'normal' is either the same book band, or one above or below a child's own band. This is the best guided reading guidance I've found so far:
www.tgfl.org.uk/tgfl/custom/files_uploaded/uploaded_resources/3315/Teaching-Reading-Book-Bands-Objectives-&-lessons.doc
IMO there are a couple of problems with a guided reading session being so far below OP's DD's reading & comprehension ability (if her DD reads and comprehends Narnia books then I'd sugget she's significantly beyond white band too).
Most obviously, it is unlikely you can deal with all of the suggested activities in the document at white level & beyond with a green banded book. Of course books can have many "levels" - inferences to be drawn above & beyond the literal level of the text etc, (poetry is very good for this & can have a low amount of text and low word complexity but much inference ect. to be drawn) but generally the amount and complexity of the text of a green banded book can't be that high or it wouldn't be a green level book.
Another implicit problem is that the reason for choosing a green level book could be that this is the appropriate level for the other pupils in the OP's DDs's group. I'd hope that part of the benefit of a guided reading group is that the children can learn from each other. If green level is chosen it is presumably because children in the group need to learn those skills and most of them will be reading around green level books - so the teacher can only ask questions at, or a little beyond, their level. So OP's DD isn't going to gain much from listening to the other pupil's answers, other than learning to be patient & how to stifle a yawn (where's the 'mildly provocative' icon)? And yes, I know, all valuable skills - to a point.
If the OP's DD was going up to another years guided reading group I think it's reasonable to think she'd be gaining as much (or at least more than now) from listening to the other pupils views and answers (who would at least be closer to her level).
As much as it would make a schools life easier, children do not have homogenised development and saying that G&T is "a croc" doesn't change the fact that in my own DDs class you have children still not secure counting 1 - 10 to the lad going to year two for maths extension. You have children still learning phase 2 phonics on pink books, to the 2 on Gold band (whose guided reading is currently orange, so the same, if far less extreme, problem as OP).
Whatever you want to call children whose current level of ability differs, I think it makes little sense to teach children at such different levels of ability the same things in the subjects or skills where there is such divergence. Yet isn't this exactly what is happening for OP's DD? Surely for guided reading with (normally?) a group of 6, spending 5/6s of the time listening to questions and answers so massively below your own level of ability makes less sense than going to a different class to have that session with pupils of closer matching level? Obviously you also have to balance a child's intellectual ability with a books emotional / topic content as well as a child's ability to speak up in front of older pupils ect. but some schools do manage it.