LL Menu layout - how do I reset it?

[m654321]

Just clicked on the LL menu button: the menu window opened as usual, but I've found  'help manual'  and 'install updates' on the left-hand-side (instead of on the RHS), and 'favourites', 'recently used', etc on the right-hand-side (instead of on the LHS), and the search bar at the top of the window (instead of at the bottom). 

I haven't a clue how the Menu layout got changed, though it seems to have occurred following one  of my children using LL.  How do I reset the LL menu layout to the default setting?

Many thanks for any help on this one.

Mike