Are you being treated in the NHS?
I've been doing schema therapy for several years, and I'm in the UK, but I see my T privately. I've made big financial sacrifices to do this and in my opinion it has been worth every penny. I've found it to be very helpful and in fact life changing for me.
I know there are therapists in the U.K. trained in schema therapy, but I don't know about if it's available in the NHS. It's a long term therapy (I think a year minimum and often several years).
I'm wondering who it was who shared with you the schemas they think you have? Because they would be working within a schema therapy framework. It's not actually a diagnosis like a medical diagnosis, but rather a useful way of understanding certain problems in order to address them within schema therapy.