Useful links.......
The International Classification of Headache Disorders https://ichd-3.org
The International Headache Society https://ihs-headache.org/en/resources/
Dean Watson Headache approach https://watsonheadache.com
trigger point pain referral map https://www.triggerpoints.net/head-and-neck
Find a Dean Watson certified practitioner here in the UK https://watsonheadache.com/practitioner-directory/