Please note there are heavy penalties for making false declarations to avoid paying VAT.
This form in simple terms - if you are UK resident, are buying personally (not via a business) and are UK resident - sign it.
If you are in any doubt as to whether you are eligible to receive goods or services zero-rated for VAT you should consult Notice 701/7 VAT reliefs for disabled people or contact the HMRC National Advice Service on 0300 200 3700 before signing this declaration.