Made a school boy error as I never test the horns before painting them! Shouldn’t have been surprised but discovered they don’t actually work. The hard part is getting the horns apart as the tops of the steel rivets had to be ground off and then some heat applied before I could punch out the remaining part of the rivet.
Once apart the fix was simple as all that was required was to clean the coil contact with some emery paper!
Now I just need to reassemble and repaint them.