This is the repaired/ new one, the original (or what was left of it) is just in the bottom picture
Essentially there is a piece of 1/16th plate sandwiched between the pocket and the tender side, the top of which is formed to make the centre part of the lid hinge.
The lid itself is a smidge thicker (cant remember what the original was), one end formed into the hinge front and back.
The lid on mine overhung as shown. I know the lid on 21629 had no overhang. Mine may not have been the original. I decided to keep the bigger version as it acts as a step.
