Where can I find out how much the tax credit was on past dividends?
You will need to contact the Registrars, Equiniti. You can contact them on 0871 384 2239, and the lines are open Monday to Friday from 8.30am until 5.30pm. They hold details of the last two dividend payments electronically, but would need to access their files for anything earlier. They can also provide you with duplicate tax vouchers if required.