Purley is part of the London Borough of Croydon if you wish to search electoral registers or the 1939 Register (both on Find my Past).
I am researching the history of the Jewish Viennese family that occupied my house from the 1940's to the 1990's and came over in 1939. I have their naturalisation records, but cannot get their background papers due to a change in the confidentiality/data protection laws in 2012. I have put in a Freedom of Information Request to Kew but have heard nothing so far, and the enquirer has to say what sort of information they are seeking in the Freedom of Information Request. You may find the information you are seeking is also subject to Data Protection/confidentiality, or it may not exist, or was destroyed.
Jill Whitehead, Surrey, UK