Thanks for the reply!

Nearly there… It’s now in emulationstation, but it seems there’s a permissions error on the xbmc.sh file. I’m getting an error:
sh: 1: home/pi/retropie/roms/apps/xbmc.sh: Permission Denied

The contents of the xbmc.sh file is exactly as you posted:

#!/bin/bash
sudo xbmc

Any ideas?