Ah ok, is there anyway I can reinstall the version that comes with 4.7 to see if it makes a difference?
Since PPSSPP isn't installed on the 4.7 image by default, even if you download the 4.7 image, installing from binary will still get you the current/last version. So, no - you can't reinstall the old version from RetroPie-Setup.
Ah, I never realised that. Sounds like I’m out of luck then.