There are many informative national home education websites that detail at great length the various legal aspects and general advice that home educators need to know. So, if you are looking for more information about how to de-register your child from school, advice about local authorities, learning styles or curricula, exam options, etc... you may find some of the links below helpful:
Home Education UK - extensive online resource and knowledge base for home educators.
Education Otherwise - "UK-based membership organisation which provides support and information..."
HE-Special.org - information on home educating children with special needs.
HEAS - "... advice and practical support for families who wish to educate their children at home"
The Home Service - help and advice for UK Christian home educating families.
IHSAN - Islamic home schooling advisory network
Local Authority websites for the South East region.
You are not obliged to inform your LA about your decision to home educate or indeed have any contact with them. However, if you de-register your child from school, the school has a duty to inform the LA, who then may or may not make contact with you. If your Local Authority does get in touch, it is probably prudent to acknowledge their communication, but it is your choice as to how much information you provide and the manner in which you wish to communicate with them. You do not have to meet with an LA advisor/inspector unless you wish to do so.
Below are the links to the Council websites if you wish to contact your local authority EHE department. Local Education Authorities do vary considerably in their attitude towards home education and what they understand their duties to be. Unfortunately this leads to home educating families having quite different experiences with their LAs; some good and some bad. Therefore it may be helpful to speak to a local home education group or HE families in your area first to find out what your LA is like.
If for any reason you want to know what personal information the County hold about you or your family, you will need to make a request under the Data Protection Act 1998.