Hi
If you still complete a Self Assessment then you will need to declare the gift aid payments made.
If filing online on the tailor your return page 3 of 3 you would answer yes to the question 'Did you give to charity?'
This will then open the section to declare the gift aid payments. If the paper tax return you would enter the details on page 4 of the SA100.
If you no longer complete a Self Assessment tax return then you will need to contact HMRC with the details
Income Tax: general enquiries
Thank you