Mac user name is causing irritations
At one time you must have used "lesleyxxx" as administrator account.

Terminal shows "Simon-Desktop:~lesleyxxxx$"

Simon-Desktop is the name you gave it in the system preferences- Sharing (you can change it there.

the ~lesleyxxxx part shows you are using a home directory called ~lesleyxxxx.

That is because you are logged in as ~lesleyxxxx!- Change that in Users &amp; Groups.

You can also delete other users but be aware they settings will be deleted as well.