Richard, thanks for the warning - I realised there had to be a reason for the ground switch method but in my frustration simply fought for hours attempting the right way without success. (Hence the pants-down emoji)... Please do provide further instructions for us to learn the best way. I was trusting the fuse to protect everything against a catastrophe whilst avoiding the steering wheel push which I find needs a firmly centered thump to make it properly work. I now have a choice of which horn to press.
