Hampshire’s county archive with access to a mass of local documents. This site takes some practice to navigate!
https://www.hants.gov.uk/librariesandarchives/archives/services/community-archives
The National Archive giving access to a 1000 years of history.
https://www.nationalarchives.gov.uk/
The Community Archives and Heritage Group bring together bodies and organisations concerned with community archives, and provide a forum for the regular exchange of views and information.
https://www.communityarchives.org.uk/
The largest guide to Museums in the UK