The replacement screen also exhibited backlight bleed to the bottom on the left-hand side. Rather than send it back again, I decided to inspect the screen assembly for a cause and found that without the bezel there was no backlight bleed. It was infact the bezel pinching the screen in this area which was causing the bleed.
Following a chat with the supplier, it was decided that the only solution was in placing carefully sized adhesive foam packers within the void to alleviate the pressure on the screen caused by the edge of the bezel. After a bit of tinkering, I had 100% success and now have a backlight bleed free laptop screen. Building up the depth of the packers with layers of thin strips was the key to finding the right thickness without causing the bezel to noticeably bulge.