I just tried to search and could only find conversations about year 2 and year 6 SATs. DS did some last year in year 2 but he did some this week too, do they just do them every year, but some are important and some aren't?
Also, what do the scores mean at this stage? He got 4's in all subjects, I assume this is okay (he hasn't been struggling afaik) - I wish they would communicate more with us parents, it's changed so much since I was at school! 