New Seedbed Frame (ooh) stopit!!! but it's fun! It's scary!!!

I made a frame today to fill with fine topsoil and use as a trial outdoor seedbed. Also maybe for carrots or something later in the season. (or maybe more seeds). It is made of decking from (where else) B & Q. The frame is just under 4 foot wide to fit inside the bed sides, so I can get two long sides from a length of decking cut in half. The shorter sides are three foot.
I don't know whether the long corners were a good idea or not yet. The idea is to use them as a frome for netting etc. or to add another level, but I am also toying with the idea of leaving them flush and fitting a lid, or rebating them and slotting in various modules on top!!! Decisions decisions. Making this wasn't all plain sailing, though...