Found it, where Rita said. Need to lie on the floor and look upwards - mine's also early 1998, Mike, but it's a diesel so just have one horn, almost inaccessible to those with normal hands and fingers.
Have checked fuse, have checked relay (which makes a noise) and have checked wires to a surprisingly clean and newish looking horn (although having had the Bongo for seven years, it can't be that new ...... the dirt obviously doesn't get that far! Not looking forward to trying to replace it, as it still doesn't work.
That under-the-bonnet shot puts mine to shame ...... it's grim under there. Leaves, pine needles, dead stuff, cobwebs. To think, the body shop were in there with all their silver paint. The painty bits look fab. I really must make more effort
