Cleartype is also available as a global option in Windows - perhaps something to try...
Control Panel>Display>Appearance>Effects and choose 'cleartype' from the dropdown.
Nail - hammer - hit - head!
Nirvana has been achieved.
I can now make yet another entry in the rapidly expanding file headed: "Why didn't I think of that?"
You'll have noted that I didn't name the manufacturer of the the two monitors, which is perhaps just as well, but both are performing equally well.
Thanks for your help, JamesT73J.
You could maybe try going to the manufacturers website and updating drivers for it.
Thanks for that tip mj. I did try the driver route as I wasn't convinced that the original install routine was successful.