If you bought a Guardian policy before 2017 you should contact ReAssure. The Guardian historic business was bought by ReAssure in 2016. This business was mainly made up of life policies, pensions and annuities. You can contact ReAssure at reassure.co.uk
Guardian policies can only be bought through Financial Advisers, as they can help you get the best solution for your needs.
You can visit unbiased.co.uk to find an adviser in your local area.