You could try:
1Please provide full details about your client as follows
a.Their full name and any trading names which they are known by which may be relevant to the request for payment
b.Their legal status (eg Ltd Company, Partnership, Registered Charity). If more than one answer is relevant, give all relevant answers.
c.Any registration numbers relevant to the answer given in b. above.
d.Their registered office (if appropriate), and any major trading addresses relevant to the above request.
e.The nature of your client’s business or other non-business activities.
2Please provide full details of any prior business or other relationship which your client believes they have had with me.
3Please provide full details of the reasons for your client’s request for payment such as a contractual or statutory obligation.
4Please provide full details, including documentary evidence, of any contracts, credit agreements, purchase orders or other relevant information regarding the request for payment.
5Please provide full details, including documentary evidence, of any goods or services delivered, including dates delivered, unit prices and number of units delivered.
6Please send me appropriate tax invoices for each of these deliveries which comply with Directive 2001/115/EC, s24 (2A) Finance Act 2002 and applicable VAT regulations. If your client is not registered for VAT, please give full reasons for the non-registration. If your client believes that the requested payment relates to an exempt supply, please give details of the appropriate section in the VAT regulations under which they are claiming exemption.
7Please provide detailed explanations of how the answers given in 5. and 6. above relate to the details provided in 4. above.
8Please give full details of any future payments that may become due under any agreement/contract referred to in your answer to 4. above, including for each payment the date it will fall due, the amount of each payment, the circumstances under which it will become due and the nature of any goods or services that will be supplied in consideration for such payment.
9For each agreement/contract detailed in your answer to 4. above, please give full details of how they may be cancelled, including any required notice period and any settlement payment that may be required to conclude the agreement.
It's a perfectly reasonable request, and information they should have, and be happy to provide.
