sb34, just wanted to say, please do not feel that this report business is a judgement of your parenting skills. I know how gutted you feel about the teacher's surprise verdict. I have ben there too - firsty with son number one, and possibly with son number two. I've posted elsewhere on this (see hyperactive thread) but basically his new nursery want him to see an SEN person, just for observation, they say - to rule out things and suggest strategies for his behaviour.
I was shocked when I heard about this - he had a problem-free term at his first nursery (I kept in close contact with the staff)and I find him better behaved and easier to cope with than his older brother was when he hit this age. His older brother was never singled out for SEN assessment at nursery.
Yet it was only 10 days after my youngest son started his new nursery that they dropped this bombshell. I find it really difficult to see how they can determine that he might be special needs after this short time. No incidents occurred in those 10 days apart from him being involved in a snowball fight.
Anyway, back to your question, having had my sons at a range of nurseries and schools in our borough, I can say that behavior assessments and strategies vary tons from one place to the next. Your son might just be at a school where they are very keen to put children on report.
And another thing - if that's the case, I bet my bottom dollar that your son is not the only one in his class to be put on report. Whenever my sons are singled out, my first question to the teacer is ' how many others in his class are having this as well'. In one reception class over half the boys were put down for preliminary SEN assesment!! And in my youngest son's nursery, he is one of several in the class of 16 children who will be seeing this SEN person.
Knowing this put things into context better. Unfortunately few teachers will tell you this - you are left to stew and worry that your son is unique.