Afraid that's not going to work; there's a groove to show where the cable should go, and the clamp has bits on it to stop ham-fisted DIY'ers like myself from doing it any other way.
I think @goo_mason and @screenman have cracked it. With a little delicate re-aligning of the hanger, things are a lot better. Still not spot on; but I can be a touch anal about mechanical stuff being "just so". I will do some more trial and error efforts at alignment - or buy a new hanger and take it from there. Thanks for all suggestions.
Do not buy a new hanger, buy a hanger alignment tool. I would say it is one of the most useful tools in my box, never once yet checked a hanger on any bike that does not need tweeking slightly.