Have seen this thread.
TFM, the levels he gets in the SATs shouldn't affect the rest of his schooling negatively - they are there for the government to check on the school (value-added KS1 - KS2). The level that he gets will just be a snapshot ofwhere he is at towards the end of Year 2. They don't count for anything important. The teacher already knows what level he is at and will be (hopefully) helping to make progress, whether he is working towards level 1 or above level 3. What I am trying to say is that lots of boys, particularly Summer born, take longer to "catch on." This doesn't mean they are failures if they don't get the "right" level.
SEastra, in effective schools those struggling would be picked up on and have extra support, probably in a small group. Do you know if the school is doing anything extra to support him? Have you had any informal chats with his teacher to discuss how he's doing?
FWIW, difficulties with organisation, reluctance to put pen to paper, difficulties concentrating because of poor short-term memory, etc can be indicative of dyslexia and other Specific Learning difficulties. Don't panic! Just keep in contact with the school about what they are doing!