It's a little disturbing to see a cable end labeled as "Battery #2 Positive" attached to the negative terminal of battery #1... but I assume that's the correct cable between the batteries, just swapped end-for-end. If the battery posts are the same size (some batteries have deliberately different sizes on positive and negative posts to things don't get hooked up backwards) then this works - since electrons don't care about labels - and is just confusing.
The clear block is a big fuse, and the block with tab it is mounted on is a holder designed to go directly onto the battery post (the battery post goes through the hole in the tab). I think this is a great design... but it is apparently too tall for the box. The steel strips are two different workarounds to make it fit.
RWS, I would describe your steel adapter as a "J" shape. It seems to exist to turn the stud through the fuse horizontal instead of vertical, so I assume the long arm of the "J" went onto the battery post, leaving a horizontal hole in the short/curved end to which the fuseholder's tab is bolted. I believe that Robert is describing the same thing:
Originally Posted by rbryan4
... OR, try it the other way, with the flat side of the curved piece attached to the battery first, with the curve pointing UP. Then attach the fused wire sideways through the hole remaining in the curved bar. One of those should work, and provide the clearance.
For future off-seasons, the steel "J" adapter and fuse holder could just be left attached to the battery, with only the cables removed from the fuseholder's stud.