Thanks for your reply Jenny,
That response seems to be so tantalisingly close to a solution and yet frustratingly a miss because the information given in that note is missing any useful information as to where the folder actually lies. "nested deep inside the ~/Library folder" is not enough of a path, to be of any real use. The ~/Library folder is vast and very full and my searches across the entire drive give nothing containing those names..
Also, the path I have given in my OP, on User Voice, does not contain the folder names given in the article.
/Users/username/Library/Containers/com.microsoft.rdc.macos/Data/Library/Application Support/com.microsoft.rdc.macos
I have tried deleting the folder at the end of the path but this basically does a full reset on my Remote Desktop app, deleting all connection and authentication settings.
Are there, perhaps, some hidden folders or files, within the folder, at the end of the above path, that might be consuming all this space?
Regards and the best of the season,
David.