INTM333270 - Double Taxation applications and claims: Vouchers: What to do if the claimant has difficulty in providing vouchers
In exceptional cases the claimant may be unable to provide an orthodox voucher to make his claim valid. It may be helpful to remind the claimant of the provisions of CTA10/S1100(1) and ITA07/S495, ITA07/S975 and the consequent obligation of the payer to provide a voucher.
But if the claimant does not wish to take this up with the payer, you can accept satisfactory reasonable alternative evidence of receipt of the income, and of the deduction of tax. If you accept as evidence a letter from the payer, or a bank pass-book for example, you should remember that the appropriate HMRC Office may be able to help by confirming the deduction of tax.