The 6v horn on my M-type hass finally expired, having been subjected to 12v too many times, so perhaps it is time to put a 12v horn on. a lucas "Altetto" or similar would be ideal.
Thanks Simon. I have had a look at the site; it is a bit complicated to navigate round and to find what is for sale. The prices seem a little high, but then again hopefully you get what you pay for. So I'm still looking for a horn that works, but needs cosmetic treatment.