If your gynecologic workup (including colposcopy and skin evaluation) is completed and there are no identified issues or lesions, this may also be a musculoskeletal/myofascial issue. Please locate a licensed pelvic floor physiotherapist (they abound in UK and the rest of Europe), and see if they can replicate your pain symptoms during a detailed pelvic floor exam. If the symptom can be replicated, it can usually be treated with musculoskeletal therapy.