- you do not have to have a visit. As the law stands, that is totally totally optional. Can you think of anything you would gain from one? If not, say no thanks.
- You do not have to fill in any forms. Again, they can ask all they like, but demanding that you should fill one in would be completely ultra vires (beyond the law).
You do not have to defend your decision to HE to them, to us or to anyone. All you have to do it produce evidence to the LA, if asked for it, that would satisfy a reasonable person that your son is receiving an education suitable to his age, ability, aptitude and any SEN.
Look at the 2007 guidelines, which are still in force: here. Look at the various ways suggested for producing evidence. You might like to provide a brief description of what you've been doing recently, or you might like to provide a description of your educational philosophy. Look at the Education Otherwise site for examples (I think there are some there).
Then, you write to the LA.
You say
"dear XX,
Thank you for your visit. I am writing to let you know that we would prefer all contact to be in writing from now on, as is supported in the 2007 EHE Guidelines. If you would like any further information about the educational provision we are making for X, please let us know".
Ball in their court.
When they write back and say "yes please, more information. Here is our form, did the dog eat the last one?" you write back and say "I would be delighted to provide further information for you. Rather than filling in your form, I would like to provide X [ed phil/ description of recent activities/ a folder of work/ whatever] in accordance with the 2007 EHE Guidelines. Would this be acceptable?"
Then they write back and say yes, and then you provide it for them.
Don't allow yourself to be bullied. And don't agree to anything you feel uncomfortable with until you've asked advice here or on HE lists about what you are legally required to do. Some LAs are professionally invested in pulling a fast one; others capitulate very fast when they realise a family actually know the law.
Congratulations. You just became a dissident in our socialist paradise!