Just got ADHD referral but I didn't choose

Hi so I'm not sure if this is common (probably is) but I've finally gotten my ADHD referral and I asked to do right to choose, but I was just referred straight to ADHD 360, I was sort of expecting maybe a list of people I could choose from or something like that but when I asked they had told me they had already sent my referral, I was wondering if the referral has already been sent is it too late for me to ask to change the provider ? I mean ADHD 360 could be good but I honestly have no idea, any advice would be great