Thanks everyone for taking the time to reply.
When I collected DS yesterday from school, his teacher came over to me.
She asked me to pop inside for a chat. She had out his books/work and we went through them. He was a 1a/2c last year, (apparently!), but has now just recently moved to a 2B????
I am very dubious and doubting in the timing of this move to 2B, but she did show me his work and showed me a check list of things that he needed to do to move on to a 2B, and he can do all of those things, so I'm not going to question it.
I did question why nothing was said at the previous 3 parents evenings, and was told that he is making progress - it may not be as fast as he was making through nursery/reception/year 1, but in their eyes, its progress and there was no cause for alarm.
His teacher has given me a copy of the targets/check list for moving from a 2B to a 2A, so I can support my DS with this at home, particularly when doing his homework, its useful to have something to work with and know I'm working alongside with the school in knowing what he needs to a accomplish.
I'm glad I kept my cool, (this time) 
freetrait I've tried to forget about levels, etc, but its difficult when you know you have tried to give your DS the best start off in school, for them to let him coast along and drop further and further down, don't get me wrong, my elder DS12, was at the other end of the spectrum - he wouldn't hardly write anything, hated school, every parents evening was a nightmare, so I know I'm lucky in that respect but my DS7, he loves school, learning, especially maths and science, we are doing experiments most weekends, I won't tell you how may times we've been to the Think Tank, (Birmingham), So the zest is there to learn and I feel they don't use that to their advantage.
I have noticed he has progressed in his literacy at home only as far as his writing, I used to say he had giants writing, its now much smaller, neater and he is grasping really well joined up writing - now this was after at the 2nd parents evening his teacher mentioned about his hand writings, so I have been working with him to improve this.