Hey Nijel & Team,
So understanding that this may not be resolved, I did try the Classic Shell add-on/modification. A few things of note for others that attempt this and some general info if others need to take this path to get this to once-work again.
1) Classic Shell is no longer supported by the above-mentioned web link (the website does still work). The Developer decided to hang up his hat on this and make it Open-Source where others can still develop on it. The developer did state he would be taking down forums, etc. within 6 months of the announcement (now almost three years ago), so never know how long it will remain. Main page does have links to the Github location.
2) It is on Github and the name of the program has been changed to "OpenShell":OpenShell on Github
For those wondering, yes, the current version on Github (4.4.152) does install successfully on WIndows 10, and does get around that annoying screen shrink issue that came with the latest/last patch from Microsoft, 2004 when using Remote Utilities on a Laptop, with the lid closed.
"Use legacy Capture mode" is still required in order to get around the black-screen issue also reported when lid-is-closed and Windows 10 has been patched to version 2004. OpenShell does not resolve that neither.
Finally, Microsoft's next update is expected around November, we'll see if there are any improvements that help out Remote Utilities.