Okay, so I've got some more questions. They're maybe a bit more general over all but refer back to the MLP build.
I'm giving a Recalbox option a go and have pulled over some rom files to test it. Most work fine but some won't load at all, blacks creen and back to menu vibes going on. These worked perfectly in the MLP image. I've tried them in FBA, FBA-Libretro and Mame in the recalbox build because it doesn't have the same centralised Arcade folder that you find in current Retropie builds.
Some are working but not full screen in Mame, others won't run in Mame and run really slowly in FBA-Libretro..
So, I guess my question is – How can you see which exact emulator is running a rom when it's stored in the Arcade folder in Retropie?
I reckon if I can crack that, I can get the Recalbox build doing what it should.
Also, (probably better to ask on a Recalbox specific site) how do you force games to run full screen? There's no option to exit to Emulation Station and set it up there like you would do in Retropie.
Thanks again for your patience! J