You are dealing with a lot. The things you shared about your parents are just horrible. I never understand when parents are not supportive. They should be on your side and show that as well. Suzi made a good post. I am not in the UK so I have no idea on practical help.
One thing that did pop out is where you wrote they do not believe in mental health. I tend to think that are narrow minded believes. And they do not help at all.