My son was diagnosed by an OT to have SPD. He was sent to OT by the school. He is nearly 7 and I have fought all his life to get someone to figure out what is wrong with him. Banged my head against numerous walls.
I am convinced he has other disorder/s and don't know where to go for assessment.
I live in the uk.
His paediatrician has known him since he was little and I feel I am being fobbed off with "it what his mother took when she was pregnant" as you probably gather he is adopted. Have tried to speak to after adoption and they can't or won't help.
Now where do I go from here. He has never been fully assessed and I am wanting him to be so I can help him with his issues before I go mad.

Have you taken him to a Pediatric Neurologist? My son does the head banging thing too. We actually had to get him a helmet because of how bad he would hurt himself. Even gave himself a skull fracture. I would defiantly look into having some kind of pediatric neuro check him out. My son has SPD too.. but we are looking into him having some other disorders too. He also just had genetic testing done too. I would ask your Dr. to see if they can do a chromosome work up on him too.

We recently got another piece of the puzzle when our daughter was tested for ADHD and it came back extremely likely. The test was given by the school psychologist, along with questionnaires filled out by me and the kindergarten teacher. All three came back with the same results--highly likely ADHD. I agree with your feeling that you are being "fobbed off" by the pediatrician. Attributing it to the birth mother doesn't give you a diagnosis and a treatment avenue. Although nothing has been the "magic potion" for our daughter, everything we've tried has provided some improvement in her behavior, function and well-being. The Feingold Diet caused the biggest improvement in behavior and toileting, therapeutic listening helped to lower frustration and impatience, OT has helped with balance and surprisingly speech, probiotics have helped with focus/attention span, and our most recent find was an Australian book called Ten Gems for the Brain (ebook) which has really been helping with learning and reading. Last summer we had to fight to get her to do one workbook page per day and after a month of the exercises in Ten Gems, she's asking every morning to do a page from six different workbooks, recognizing more words and beginning to read. I'm not saying you shouldn't seek other diagnoses if it will help you get more services, but there are also additional things you can do at home to move him forward (but I know it's exhausting ) You're doing great, and I always appreciate your posts and input!