You need to use P-scales as an assessment tool just as you would use APP or any other level descriptor. I'm assuming this child is on the SEND register? What are you doing for them that is different from the provision available for the other children in you class? I've got to ask you whether you think it is appropriate given that this child is working at P7 (and therefore counting reliably to at least 5 and counting by rote up to 10, which is in my opinion nursery/early reception level ) to be doing such activities as you describe or whether actually it would be better use of their learning time to be working on their next steps in their learning rather than working alongside others who are working at a higher level. For example when talking about the weight of objects it maybe would be more realistic to expect him to say which is heavier/lighter out of two objects and work out how to record this, which would be working towards 1c. From what you are saying '' I could just say L1 because there's evidence in his Maths book, but this isn't going to help him if he's moved on before he's got basics - like number formation. He doesn't reliably form any numbers, even 1-5, even when he's copying them down, which makes me very unsure..'' I would say that you are not happy giving level 1 and in which case I would say that the child hasn't acheived it. Remember you know the child best, would you award level 2 to a child who can only acheive level 2 standard work when working with an adult?