Here is a version of the command line which worked (Google Bard helped but didn't "understand" that inverted comma's weren't a part of the line and it added something from wherever it tried to source this secret code from. dism /Online /Remove-Package /PackagePath:C:\Windows\servicing\LCU\Package_for_RollupFix~31bf3856ad364e35~x86~~19041.3803.1.3
After a re-start it seemed that it looked like a re-install of Win. 10 but after offering a few options that disappeared and all apps. etc seem normal. The name comes from the LCU package itself and the path is from Location in the folders "Properties".