I just change the version number and nationality in the link to get what I want.
I really don't know why Graphisoft don't have a clear link to all of the older versions - or maybe I just can't see it.
I can easily find links to all the old add-on, etc., just not the actual program.
One of the forum moderators. Versions 6.5 to 25 Dell XPS- i7-6700 @ 3.4Ghz, 16GB ram, GeForce GTX 960 (2GB), Windows 10 Dell Precision 3510 - i7 6820HQ @ 2.70GHz, 16GB RAM, AMD FirePro W5130M, Windows 10