Second - in our area at least, in KS1 once you are working at NC Level 3 you are told you are, but they won't tell you the sub-level (same for formal SATs results). Suffice it to say if you are told your DC is working to Level 3 this means they are working well above expected level of achievement and are doing well.
What you need to bear in mind though is in KS2 (Y3 - Y6) your child should make at least 2 full levels of progress above what was achieved at end of KS1 (end Y2 SATs). So if your child achieved NC Level 3s in English/ Maths/ Science - you should be expecting NC Level 5 at least by end Y6. This is really important, because this is considered a reasonable expectation and a good school would achieve at least this. What you really want to see is them stretching our child slightly beyond - but that would mean your school is outstanding and that's not all schools.