It's okay I found the answer to my question in the 'Gimp Chat' Forum.
In case it would help anybody else here is what helped me -
'Open GIMP while logged in as your administrative user.
Open the "Edit->Preferences->Folders->Brushes" page and check the "Writeable" box next to the path "C:/Program%20Files/GIMP-2.0/share/gimp/2.0/brushes/" (or somesuch). Close the Preferences dialog.
Open the Brushes dialog ("Windows->Dockable Dialogs->Brushes") and activate the offending brush. The trash can icon should no longer be grayed out, and when you click on it, you will be asked if you want to remove the brush and delete its file from the disk.
Afterward, change your Preferences back so that system brushes are no longer writeable, close GIMP, and log out of your administrative account.'
I am so happy now I have been able to get rid of my second brush and in the process I have learned in future if I create any more brushes to save them in my personal brushes folder and not in the Program system folder.