Energy Performance Certificate Retreival To retreive an Energy Performance Certificate previously carried out by LW Diagnostics you have two options. The first is to contact us and give us the Unique Identifying Number, or UID, allocated to each EPC and we will forward it onto the invoiced address. Or if you do not know this contact your solicitor or estate agent. The UID is a set of 5 groups of 4 digits and is found on the top of the first page of the Certificate. Alternatively, if you know the UID you can do the following: 1 Goto https://www.hcrregister.com/ReportRetrieve 2 Enter the UID number located in the description of the dwelling, which is 5 sets of 4 digits. note: you must ensure that you include the dashes. example: 1234-1234-1234-1234-1234 3 View the EPC and/or save it for later.