I know this thread is a little old but I just thought my experience might help the OP if they are still checking.
My DS sounds very similar to yours, regularly at the top of his class, can focus but has issues with hyperactivity and impulse control.
We thought he would maybe grow out of it, but he didn’t. We eventually had a private diagnosis and did titration privately too. Then switched to a shared care agreement with the GP. We don’t use medication every day, just as and when needed, but it does really help our DS.
You mentioned that your DS was diagnosed by a psychologist? Only a few psychologists are able to properly diagnose ADHD. It’s usually done by psychiatrists (and occasionally specialist paediatricians) and they are the only ones who can prescribe medication. This could be why your psychologist hasn’t moved forward with that perhaps? If you have a private diagnosis you have to do the titration period (to find the correct drug and dose) privately as well so the costs really do mount up.
NHS waiting lists are several years unfortunately and most Right to choose providers won’t do children either anymore.
Also, just be aware some GP’s will not do shared care agreements unfortunately.
I agree with the other posters that have said that there is nothing to fear from getting a diagnosis & trying medication, and it could also really help your DS.