Resolved it, don’t delete ‘prboom.wad’ out of ‘~/RetroPie/roms/doom’ as RetroArch looks to this path for it despite it being here: ‘~/RetroPie/emulatorcores/libretro-prboom/prboom.wad’
This means however you’ll get a rom list like this in emulationstation:
DOOM.WAD
doom2.WAD
TNT.WAD
PLUTON.WAD
prboom.wad
