Home Education UK - extensive online resource for home educators.
Education Otherwise - "UK-based membership organisation which provides support and information
HEAS - "... advice and practical support for families who wish to educate their children at home"
HE-Special.org - information on home educating children with special needs.
Home Education in the UK - all aspects of HE covered with a more personal touch, plus useful links.
THENuk - a national, not for profit network of support and resources for home educators.
Funding Central - Useful site if you run a home education group & need to find funding possibilities.