If you are looking for all certificates (closed and live) for one particular property:
Go to Lettings properties > View Properties > Search for the property address
Expand the View dropdown menu > select View Certificates
This will take you to a page where you can view all safety certificates for this particular property (past and current). You can also add/renew safety certificates on this page.
You can filter these results by using the search box (ie search Landlord Gas Safety to narrow down the results) or use the expiry date filters.
For example, if you are looking to locate a specific certificate that expired in August, you would click on Change date range and set the expiry date range as follows: From 2019-08-01 To: 2019-08-31. This will filter the results to show only the certificates that have an expiry date in August.