As you are aware accessibility is a complex topic and the language used and the documentation is not understandable to many clerks and councillors. Listed below are some resources that may help you to understand the regulations better. 

W3 - The Standards
https://www.w3.org/TR/WCAG21/

Government Portal
https://accessibility.campaign.gov.uk/

Free Web Evaluation
https://accessibilityinsights.io/

Sample Accessibility Statement
https://www.gov.uk/government/publications/sample-accessibilitystatement/sample-accessibility-statement-for-a-fictional-public-sector-website 

Doing a Basic Accessibility Check
https://www.gov.uk/government/publications/doing-a-basic-accessibility-check-if-you-cant-do-a-detailed-one/doing-a-basic-accessibility-check-if-you-cant-do-a-detailed-one

Checking PDF Documents for Accessibility
https://www.gov.uk/government/publications/doing-a-basic-accessibility-check-if-you-cant-do-a-detailed-one/doing-a-basic-accessibility-check-if-you-cant-do-a-detailed-one#pdfs-and-other-documents

NALC
https://www.nalc.gov.uk/news/entry/1495-nalc-launches-new-publication-on-website-accessibility

Vision ICT
https://visionict.com/_UserFiles/Files/Website-Accessibility.pdf
https://visionict.com/WCAG_2.1_Checklist_28396.aspx
https://visionict.com/The_Importance_of_Accessibility_32145.aspx 
https://visionict.com/DDA_Compliance_25682.aspx