I think GooseyLoosey's post is interesting. Her ds is officially on level 3 but she knows he can read the level 7 books.
Presumably different teachers do things differently in terms of how many books have to be read at each level.
It's not a race, all children develop at different rates and teachers do need to be sure that the children actually understand what they are reading, learn about punctuation and expression etc whilst they are working their way up to longer stories with more varied vocabulary and a more interesting plot.
I like the look of the poetry books, our school don't seem to use them so I might buy some for ds although he still have his favourite cat in the hat books which are a bit like poetry and he loves re-reading them.
Like I posted earlier, ds is currently finishing level 9 but he still really wants lots of colour pictures to accompany each story and his handwriting is definately that of a 5 year old. There are, without doubt, children in his class still on the 1+ stage and loads on level 2. I notice that the book baskets in the classroom are mainly full of stage 1, 1+, 2, 3 and some stage 4 books so this is presumably the norm. I don't know where the level 9 books are from (maybe class 1 ?).
The OP asked "Go on honestly what reading stage is your reception class child on ?" and I participated in the hope of contributing to an overall average being established but I do appreciate that this attempt could be skewed by mums only posting if they thought their child was doing well and keeping quiet if they didn't think so.