Our school is refusing to give us more information other than the level. I'm sure we're entitled to know sublevels/scores?
I'm not sure about the legal position, but have they told you what their reasoning is? They will almost certainly have to pass that info on to your DC's secondary school, so I suppose if the primary is being really obstinate and you don't fancy fighting them, you could just wait and ask the new school. KS3 targets are normally +2 full levels so that should give the game away?
DS1's KS2 SATs were the year that most of the marking seemed to be up the creek; I don't remember being told anything except months later that he had got level 5's in everything and not being too bothered about sub-levels. DD was told sub-levels - 5a Maths and English, 5b Science - and was very proud of her 95% in Maths even though she didn't get the level 6. We have yet to find out what the school will tell us for DS2.