Deleted Toolbar Won't Delete

I recently downloaded a macro which came with it's own button on it's own toolbar. (I can't remember the developer, but it's called Multihide and simplifies the hiding and unhiding of worksheets).

Now, I've copied the button onto my own toolbar, and tried deleting the toolbar (by the usual method - Cursor over toolbar, R-Click, Customise, highlight toolbar name, delete) which came with the macro, and although it at first looks as though it's gone, when I next restart Excel, it's there again. I find I can't delete the button from the toolbar either, nor delete the whole toolbar.