I am registered disabled - can I claim VAT exemption for my orders?

This depends on what products you wish to purchase.  The product must be specifically manufactured or designed for the purpose of supporting a person with registered disability.  For example, a wheelchair or a hearing aid device.  Exemption does not apply to products that are manufactured for general use and without the specific purpose of supporting a person with a disability.  Examples of non-exempt products would include items like vomit bowls, dressings and plasters.