Community Matters
http://www.communitymatters.org.uk/

LASA
Established in 1984, we’re dedicated to supporting organisations in their use of technology and the delivery of social welfare law advice to the disadvantaged communities they serve. http://www.lasa.org.uk/

Advice UK
Does your organisation give free advice to members of the public and your community? Are you independent of local and national government bodies? Then you might already qualify for membership with AdviceUK!
http://www.adviceuk.org.uk/

NCVO
NCVO champions the voluntary sector and volunteering because they’re essential for a better society. We do this by connecting, representing and supporting voluntary organisations. https://www.ncvo.org.uk/

Citizens Advice Bureau
https://www.citizensadvice.org.uk/