effectively a VAT invoice i.e. that dicloses VAT payable is only required when invoicing another VAT reg. business or a VAT exempt business in the revenue notice a taxable person means a VAT registered person.
Is your question: Should you charge then VAT then the answer is YES unless they inform you that the are exempt from being charged VAT the section 13B. You are registered the fact that they are not or conduct an exempt activity is not an issue for you.