Here are some other organisations which you may find useful:

PoTS UK (https://www.potsuk.org/) Providing information and support about postural orthostatic tachycardia syndrome (PoTS) for sufferers, medical professionals, family, and friends

Pain Concern (http://painconcern.org.uk/) Work to improve the lives of people living with pain and those who care for them.

Ehlers-Danlos Support UK (https://www.ehlers-danlos.org/) 

Brittle Bone Society (https://brittlebone.org/) supports people with Osteogenesis imperfecta

Stickler syndrome UK (https://stickler.org.uk/)  is a non-profit organisation that provides information for families, healthcare and medical professionals affected by or caring for people with Stickler Syndrome.

The Arthritis and Musculoskeletal Alliance (ARMA) (http://arma.uk.net/) is the umbrella body for the arthritis and musculoskeletal community in the UK.

Pain UK (https://painuk.org/) an alliance of charities providing support and help for those living with pain. Pain management, healthcare advice. tips and resources available.

The Ehlers-Danlos Society (https://www.ehlers-danlos.com/) Formerly the EDNF,  support collaborative research and education initiatives, awareness campaigns, advocacy, community-building, and care for the EDS and HSD population. They're developing a Global Registry of patients with EDS or HSD