I have experience with meds for DC for 10 years and from my experience what I hear a lot on this board, they work. They work fast and make a day and night difference. They don't solve all problems, but go a long way and are an essential first port of call imo.
My experience is with Ritalin (Methylphenidate), Concerta (Methylphenidate slow release) and Strattera (Atomoxetine). Ritalin is short acting and creates a roller-coaster when it phases out after 2-4 hours and when in phases in after the next dose is taken in the afternoon. This creates problems of its own and require huge organisation and discipline, which is not the strength of people with ADHD. So you need Concerta really, which is continuous release throughout the day and lasts 10 - 12 hours. However we started on Ritalin before moving to Concerta, it is the recommended procedure, I understand. You start on 2.5 mg of Ritalin and go to 5 mg after a few days, then to 10, you stay on 10 then go to 15mg after a couple of weeks. It is body weight dependent. Going straight to 10 mg or to slow release can trigger stronger side effects and create more setbacks, it's important to start little by little. You should be seeing a difference after a couple of weeks and be on the optimal dose of Ritalin in 4-6 weeks. A good Psychiatrist would move to Concerta after 2 months.
There was a recent thread on side effects,
www.mumsnet.com/Talk/special_needs/3482078-Positive-stories-of-ADHD-treatment
I suppose you read the big thread on meds mentioned above.
Some DC discussed in there are autistic with complex needs in addition to ADHD, so you need to separate the issues. Mitigating ADHD symptoms makes ASD more apparent, more dominant, so parents react to that, thinking it is side effect of meds; it is not, it is autism showing itself anadulturated. I also note that those with problems are not on Concerta. Some of the medicines mentioned there, like Elvanse (similar to Adderall), are heavy amphetamines. They are short acting and not first line (not recommended to start with) and are not accepted by the NHS (you would depend on private prescriptions for years), so I wouldn't worry about those at this stage. I personally would not use those for my DC anyway.
Personally I think some parents overthink the medication, they project their own anxieties onto medicating, but obviously there are various experiences reflected in various threads. I remember one mum a few years ago. She started with panic and misgivings, strong prejudice about the idea of medication and once started, everything looked to her as confirmation of doom and gloom. There is not need to overthink and dramatise.
Perhaps you might ask the doctor how not to overshoot the suitable dose, how to judge whether the dose is enough without going higher, because I suppose this could cause some (mild) problems discussed by some in the big thread, mainly because they used the bazuka amphetamines or jumped straight to slow release or 10 mg dose. See here www.mumsnet.com/Talk/special_needs/1384372-Methylphenidate-Medikinet-Opinions.
The Omega stuff and supplements might be nice as supplements, but surely you don't consider them to be an alternative to meds? Because they are not and the effect is probably ...
I mean would you take vitamins instead of an antibiotic for pneumonia?
Not sure what a neurotherapy is. I suppose CBT and some coping skills or life skills training could be helpful. To learn techniques and good habits to cope with the condition if you can access this privately.
What is really essential is help at school, the SEN stuff, because meds will not solve all the problems and proper SEN support will be required according with the SEN process and procedures. Are you in touch with the Senco at school? Do you have an individual educational plan for DS?