Actually, that's it Marty. I just watched how it works and the tip of the wire actually pushes the ball forward as part of the action. This stops what is happening to yours (ball rolling backwards). If someone has a bit of that sort of wire I'm happy to bend one up to match, just don't have any of the wire myself.

I've ordered some gate wire from RTBB.  Once it arrives I'll let you know.  I may need another photo to work out dimensions as I get the feeling its probably fairly particular.