We had the same, dd started Reception much the same as yours. Bascially having missed the previous year by a week, she was soooooooo ready to learn. Nursery had done 'big girl' work with her, because she was so keen, I had done bits at home, albeit very relaxed, she could even read simple phonetic 3 letter words.
End of Reception, she was if anything at the same place when she started. I didn't say anything, as didn't want to be a pushy parent! However, in Year 1, I was told her reading was a little behind - WHAT!!! - and her letter formation poor. I was also told that all the children coming up were all a little behind what was expected, but that they would all be 'on target' at the end of Year 1.
To cut a long story short, we did Yr1, because we thought maybe we were being unreasonable and she was a good teacher, but then still feeling like she wasn't being stretched and she was coasting, moved her to a prep school, not near a good 20 mins away, it was a big decision.
The difference was staggering and she has taken a little while to catch up with them, but has just done it now and is a different child. Ironically, they seem to do a lot more 'fun playing' things, trips to the beach, lots of colouring and art, more sport and swimming. In fact one parent commented to me yesterday, when they came out with a note about another 'fun' event in school - 'is this what we pay our fees for?'. However, they do work hard too.
When we took her out of the state school, I was told by the head that they had for the first time with her Reception class, strictly followed the EYFS and it hadn't been quite right for that year group. She felt that a lot of them were capable of a lot more, but they had pressure on the LA to 'stick to the book'.
Children are different and progress and need different things, our dd basically spent a year playing - OK it wasn't wasted totally, I admit they learn a lot through play, but she was ready to learn and could have done an awful lot more.
My DH is cross we didn't send her to the Prep. initially, I too feel sorry about it, she definately could have coped with that little extra, she would certainly be in different place with her learning now.
EBD is right, although it may be unpopular, the independent sector will certainly benefit some children, especially those who get a lot of input at home before they start and are obviously ready to learn that bit more. I don't regret it one moment, even when I see the bill coming in each term. Imagine what she would have been like if she had been there from the start!
Sorry no excuses for going private, it is right for my dd.