Thanks for the advice on here although none of them resolved the issue I found the solution.
The answer is to copy the 3 Group folders in WinX from a computer that has a working start context menu and use these to replace the same folders on the computer that isn't working. The 3 folders (Group1, Group2 & Group3) can be found in C:\Users\Adminstrator\AppData\Local\Microsoft\Windows\WinX
Administrator is your user name i.e Peter.
Cant believe the 3 Microsoft alleged technicians I spoke to didn't know the answer, especially as the error first occurred back in 2016!