Hi paul2010,
See
http://www.l8r.net/install/hdc.html"gvp500hd8.dms GVP hd8 hd+ for the a500"
I downloaded this DMS and its only 373k in size.
So it will fit onto a 770k PC formatted disk.
If you have an Amiga with CrossDos you can transfer and unpack it to a floppy disk, or if not, maybe there is a CrossDos type prog you can use for your A500 to unpack it ?
Regards, Michael
aka rockape