My DD is in year 1 at an infant school. The school is very sweet, but acedemically it doesn't seem to do very well. I have spoken to a lot of parents whose children have been through the school, and then their children have gone on to struggle in a new school when the leave. I can see that the infants school doesn't have a strong academic focus - my dd never gets homework, but she is always doing a play based activity. A couple of parents have asked to see the year 2 SATS results, but as you yet nothing have been produced by the headteacher. What would you do? How can I check the school is teaching them enough to prepare them for another school?
You say your son is only year 1. At that stage play based activities are often a good way to teach children.
As someone with a child in year 6 and one in year 2, I would suggest you take the league tables with a large helping of salt. Our Primary school always did well in the tables, however, what we didn't know at the time we chose this school is that the majority of children also had tutors! It would make interesting reading if schools would included in their results how many children in their school are being tutored outside school.
If your little boy is happy at his school then I wouldn't worry too much at this stage. Imho the best way forward is to keep taps on what they are doing and how they are getting on. Also we spent a lot of time reading books together, making up simple maths games etc... What is really important is that you and your child are happy and that your child is making good progress, don't worry too much about what others are doing.
Last but not least, some school can suit one child but not the other. All kids have very different needs, especially at that young age.