INTM331252 - Double Taxation applications and claims: Self Assessment: Repayment claims from non-residents: What to do if you only receive a partial reply to your enquiry
If you receive a reply that does not provide the full information or all the documents requested you will need to contact the claimant or agent as appropriate and say what it is that you still need. You might want to add that until you have received all the information requested you will not be able to proceed with the claim. There is no special letter for this purpose. Effectively you are restating part of the request for information or documents contained in your initial letter.
If you experience continued difficulty in obtaining the information or documents you require you may wish to consider invoking the power to require the claimant to produce documents or supply particulars. See INTM331256 for details.