Fitting a second or uprated horn

[bathtub tom]

Has anyone done this?

My '14 reg looks like I need to remove the front bumper to access behind the grille where the horn's located, unless someone knows a simpler method.

Intriguingly, I've noticed an unused fuse position 2 in the 'engine compartment (type B fuse box)' - the one on the driver's side -  marked S-HORN. The owner's manual shows a 10A rating, but no circuit description. Could this perhaps denote a fuse position for a second horn and if so could the wiring be somewhere in the loom?

Any enlightenment would be greatly appreciated.