This is the panel right behind your kidneys when you sit in a Bugeye. It meets the parcel shelf that comes out of the trunk/boot. Notice the two humps in the panel that align with the stump end of the quarter elliptical leaf spring. The spring plugs into the spring box and comes to rest up against the back of this panel shown.
RESTORER'S NOTE: There are some very minor irregularities on the sheet metal on this panel. It is not a perfect match to the factory original but it is the only one available. In most cases, restorers will cut out a section to patch their bulkhead and this panel can help save time and fabrication on your restoration.