There was a bit of stray airflow on to my printed bed, so I slotted a clear plastic lid behind the board to stop unmanaged airflow to the bed. I'll also need to fit a fan-guard to the fan. I'm happy to leave it as an open sided arrangement for now.
Here's a view of the reverse side. I simply took the base plate from thingiverse into Sketchup, added a tab at the top, rounded the corners and repositioned the push-on rod mountings.