Framethrower for Pistorm 500 is available from AmigaKit and shipping now:  https://www.amigakit.com/framethrower-pistorm-p-91346.html

I bought a couple of the Atari CX78+ joypads, with the DB9 connector.

They generally work in the A600GS, sadly the two buttons don't work independently, but both do work as a single fire button control. Also another caveat I found was that there is the occasional game that for some reason won't work properly as it thinks the fire buttons are permanently on (I also found this problem with the occasional game when using it with my Turbo Chameleon cartridge). Most games do work with it though.

So it works, but with some caveats.

This is what they write on the support site: By popular demand, the Amiga Forever series always included ROMs, floppy disk images and system updates and patches also taking into account "Classic Support" scenarios (for use outside of emulated Amiga systems).
https://www.amigaforever.com/news-events/classic-support-3-1/ it's old, CF mentionet but SD not (yet?)

Thats really useful, thanks. I have the CF pictured on that page, so I guess it includes the ROMs! I wish there was a place I could download them officially.

Thanks for your help

See if you can find "cloanto amiga forever essentials" on one of the alternative android APK sites - you can copy them over from your phone USB.
Failing that try archive.org - not gonna link here though not hard to find.