What's the best type of therapy or therapist for depersonalisation disorder? something isn't working with my current therapist.

Long-term therapy: Depersonalization disorder is a complicated problem that needs long-term therapy with a professional you trust. Difficulties in this process are not uncommon, and discussing them should be part of the therapeutic work. Please tell your therapist that you feel "something isn't working." my guess is that s/he would want to know. Good luck.