I live in a 3 tier system (primary, middle and secondary) - are there any league tables or similar of the primary schools? the only ones I can find are KS2, which happens at middle school not at primary.
There are KS1 SATs as well taken at the end of Yr2 but I don't think that they publish them for small schools as they aren't statistically valid. I'm not sure what happens for larger schools. Have you spoken to any head teachers of the schools you are considering ? I'm sure they would be able to give you details of how their school has done even if its not "official".