Someone suggested that I cut down the terminal box I have by clamping my angle grinder. Off to Bunnings (large hardware store) for an aluminium cut-off wheel. The orange plastic let me slide the terminal box easily.
The bucket in the background is because the terminal box got VERY hot. I had to dunk it in water after each side. I left the corners slightly intact until the sides were cut through. I made a huge mess - aluminium shards and dust everywhere. (I cleaned it up before taking this photo - sorry!)