To drill through to the parcel-level detail from the heat map, you first need to select the country from the map and then hover over it until a pop-up menu appears. This contains two hyperlinks: Drillthrough (which takes you to the Late Parcels tab) and Late Service Level Report.
This allows you to see how late particular parcels were.
Hours Late is measured as the difference between the Actual Delivery Date and the Guaranteed Delivery Date. The First Delivery Attempt is not taken into account.
You can use the Order Numbers and Consignment Codes on the left of the tab to identify the packages in Metapack Delivery Manager.
You can also drill through to the packages from any individual cell of the main report table. Select the cell and then hover over it until the Drillthrough link appears, e.g.
This allows you to view late parcels by postcode (the postcodes are listed in order of number of late parcels from top left to bottom right), and trade lane, e.g.