"honk for space for cycling" - no no NO!

[softlips]

On the rare occasions when I've felt the need to use my (car) horn, it's such an unfamiliar device that I can't remember in time which bit of the steering wheel I have to press...

Glad it’s not just me. The event has usually passed by the time I realise where to press. I remember when one pushed the indicator stork for the horn.

[Mick F]

I can't remember using the car horn last, and me too, I'm not familiar with where the button is!

This is a Google image, but we had one of these, and the horn was controlled by the chrome ring.

[Vorpal]

it is the second picture that appears after a few seconds on ctc.org.uk

Not when I looked.

[whoof]

I regularly honk in order to ensure that motor vehicles give me space for cycling.
The final part of my commute is up hill and there's a kept left sign. If I stay in the saddle cars regularly try and squeeze between me and the sign. I've found that if I get out of the saddle and ride in some affected way lurching from side to side they wait and pass afterwards.
Perhaps this was somewhat lost in translation.