You should claim the tax relief by completing the appropriate section of your self assessment form, which can be found on the HM Revenue and Customs website. You may be liable to request a reduction in your self assessment payment, so please check the criteria before submitting your gift.
If you are not sent a tax return or you want to claim relief before the end of the tax year, you should contact your local tax office for advice. You must discuss all arrangements carefully with a solicitor or financial advisor before proceeding with the sale.
If you pay tax through PAYE (employees and occupational pensioners) write to your tax office and ask for an amendment to your tax code for the current year.
Please remember, it is your responsibility to claim the tax relief and to keep a copy of the transfer form or letters relating to the donation in order to make the claim.