Well, 3 days later, no more weird out of frame picture! I think I can safely say that it solved it. Thanks again @mitu !

This is a configurable option. You'll have to modify Emulationstation's source and re-compile to change the size of the font, it's automatically computed from the screen's height - see here.

Well I managed to do it - bit of a heath robinson solution...

From this thread (similar question)
https://retropie.org.uk/forum/topic/9078/omxplayer-default-settings-change-system-wide

I grabbed the Thin Pixel 7 font from here: https://onextrapixel.com/25-free-pixel-perfect-fonts-for-8-bit-designs/

Renamed the font file as FreeSans.ttf and FreeSansOblique.ttf (these are the two fonts that are used for the video subtitles on the screensaver), and then dropped them into /usr/share/fonts/truetype/freefont, overwriting the existing font files.

@kamen-rider glad to hear. So what file did you need to add?

@psyke83 Cheers!

@backstander I agree. Ill submit a patch upstream when I have some time.