As at 20 January 2021 the up to date immigration rules are also available on the following link: https://www.gov.uk/government/collections/immigration-rules. This is useful in that the page contains an index of parts of the rules, and then publishes each part on a separate link. Frequent reference to the rules will give you access to and understanding of the requirements of immigration law and will bolster your understanding and knowledge. Take time to become familiar with them.
Useful sites in relation to campaigning for the rights of families in Immigration Law include:
JCWI is 'an independent national voluntary organisation, campaigning for justice and combating racism in immigration and asylum law and policy': www.jcwi.org.uk.
Migrant Rights Network works for ‘a rights-based approach to migration, with migrants as full partners in developing the policies and procedures which affect life in the UK’. www.migrantsrights.org.uk/
The Refugee Council is a large refugee agency in the UK, providing policy work and advice to refugees and asylum seekers and organisations working in that field. www.refugeecouncil.org.uk/
Refugee Action is a national charity working on access to legal advice, destitution, and refugee rights. See https://www.refugee-action.org.uk/
The Kept Apart Project which is run by the Brigstow Institute at the University of Bristol can be found at: https://www.reunitefamiliesuk.co.uk/kept-apart-project