well, my son has ADD(not ADHA) he is not hyper, although his brain is his body seems quite lethargic. He is almost 21 and while i High School graded far above his grade intelligence. He uses his ADD as a crutch sometimes. He was on Ritalin during school and now seems fine without it although i have to tell him 20 times to do something before it sinks in. The is no medical test your GP can give you and a psychologist is mainly going to go on what symptoms you describe to them. this is how my son was "diagnosed". I took him to the pediatrician and they referred us to a psychologist and they asked my all sorts of questions and he then said, well, from what you've told me it sounds like you con has ADD. We got the Ritalin and it got him from a non reading stage to a reading stage in a matter of a couple of weeks and he said to his nanny, "Nanny, i think i get this stuff now"(bless his heart). Not sure if you have to be a certain age to see a GP or Psychologist in England. I think in the US where i am you have to have the permission of your parents if you are under 18, but i could be wrong. My son fought going to the psychologist tooth and nail as he got older, but now he thinks counseling is a great idea. Good for you for taking the initiative. My ex husband i'm sure had/has ADD and he was never diagnosed so alcohol became his medication of choice, hence the EX!
Good luck.
Mikala