To cut a long story short, my dh adopted my DS in 2009 after 4 year together, DS was 7 at time of adoption but have been with dh since he was 2, I told the school that DS surname had changed legally and took in new birth cert .
Fast forward 5 year and I have just received DS info pack for seniors as he starts in sept it came in my maiden name, DS who has learning difficulties then told me that he was told to write his old surname on sats papers 2weeks ago.
he didn't tell me at the time because he thought he would get wrong :( also he didn't understand why he had to do this and didn't question the teacher.
He got really upset when the letter came today, he already thinks he is different due to his various disabilities, he is very anxious tonight and has started to cry asking why isn't he the same as us 
I am seething... I feel rather peed off that the school have allowed this to happen especially as he is a very anxious child to start off with.
I even filled in his new school application form in the surname he goes by now, fgs he even has a passport with his name on.
Arrrrgggghhhhh.