Just be aware that should you find wiring in that vicinity, one of the cables will be a +ve feed direct from the fuseboard to the horn and the other a switched -ve via the horn button. Usual VW practice.
The standard bus horn should produce a pathetic, rather camp bleating noise. If it sounds more manly, there's something wrong with it
They are available in two notes: Beep Beep for a Beetle Honk Honk for a van They are in my local shop anyway - £6.50 - just like the original.
My horn goes aaaawoooooooooooooooooooogggggaaaaaaaahhhhhhh. And has passed the MOT like this 5 years running.