Further to my question I have discovered the following:
Photography plan includes:
Lightroom Classic (Desktop App) - Graphics Requirement = Direct x 12.0, Open GL 3.3, Direct x 10.0
Lightroom CC - Graphics Requirement = Open GL 3.3, Direct x 10.0
Photoshop CC - Graphics Requirement = Open GL 2.0
(Why not re-name them Lightroom - Desktop and Lightroom - Cloud)
The only difference between the photography plan trial and the applications I have downloaded appears to be Lightroom CC which appears to be compatible with my system.
I assume there are some aspects of Lightroom Classic that require directx 12 or they plan to use them in the future but can't find any information anywhere.
I had just got used to the idea of paying £120 for the plan now it seems they also want me to upgrade my Graphics Card (£200) for some reason that is not clear, as Lightroom Classic appears to run perfectly well on my system!
Thanks for the reply Jeff,
I had eventually figured out that the issue I had was with the operating system.
I have win 7 pro.
So although I can use Photoshop and Lightroom desktop apps the hosted (can't bring myself to use the term cloud) Lightroom CC only works in windows 10.
I suspect that I could still sign up for for the photo plan and just use the desktop apps but I suspect at some point (and with my luck in the middle of my subscription period) Adobe would pull the plug on those too!
Once again I'm put off this software! Oh well, never mind!
Yes, you can use photoshop cc and Lightroom Classic on windows 7.
I think it will be a while before, if ever that the Lightroom desktop program goes away, although the name Classic does make one suspicious, and most certainly not any time soon that the desktop version of photoshop will disappear.
The Lightroom cloud is very much a work in progress anyway, not having a good number of features that the desktop version has and your photos need to stored on a server, not a prospect that appeals to a lot of Lightroom users.