Thanks again Scook,
The Drum Replacer Directory is missing from my Internal folder and the Celemony Directory is missing from my VST3 folder.
Having said that, I installed cakewalk to my D:\ drive as I was running out of space on my SSD.
So now I have the main program installed under D:\Program Files\Cakewalk (without Shared Utilities), but C:\Program Files\Cakewalk\Shared Utilities\Internal also exists.
Similarly, there is no D:\Program Files\Common Files, only C:\Program Files\Common Files.
I'm sure that is where things have gone pear-shaped, I think Drum Replacer is looking for D:\Program Files\Cakewalk\Shared Utilities\Internal and Celemony for D:\Program Files\Common Files\VST3
I will create those paths and re-install both apps tomorrow.
Thanks for pointing me in the right direction, will keep you posted.
Cheers,
Peter