Thanks everyone for the piccys.
A couple of points are Groucho's piccys are of the 4 cyl type (Addit: although this one is home made*) and d@rk51d3's are the 6 cyl type. The boxes are otherwise the same in SIIA and SIII.
The holes around the sides are not for handles, but for where the boxes were bolted in place, although most people chose to leave the bolts out after the first time they removed them. If the seatbox doesn't have the corresponding holes then the box has come from a different vehicle.
* The slot at the rear of Groucho's is part of the home made design. If you look at the rear end of d@rk51d3's one, you can see a tab protruding forward. This corresponds with a tab on the underside of the cover, which when the two tabs slide under/over each other the rear end of the cover is held in place. Same as on the passenger seat box cover although the tab is further forward on the middle seat.
You can't have the tray and have a rear PTO output fitted to the transfer case as the selector top and the tray occupy the same space.
Just a word of warning, I used to keep my workshop manual in the tray, but they leak water/mud thrown up from underneath. If you are going to use one, you need to consider if the leaking is a problem to you.

