It's been ages since I posted....not much new happening in Casio world. Until today.
I found out that the almost impossible to get RA-500 RAM card for the Casio VZ synths and PG series synth guitars have another compatible card that can be used instead of them - the ES-100.
Here is the Casio VZ Facebook page discussing this find
This is great news as the ES-100 is more popular and available, and cheaper.
Hope that helps everyone.
Cheers, Graham