You can only use a VAT65A form if you are an overseas business who has incurred VAT in the UK on goods or services
The conditions are;
You are not registered, liable or eligible to be registered for VAT in the UK,
You have no place of business or other residence in the UK and do not make any supplies in the UK (other than transport services related to the international carriage of goods, or supplies where VAT is payable by the person in the UK to whom the supply is made).
Please see the guidance below:
Refunds of UK VAT for businesses established outside the UK