They appeared a couple of weeks ago, just before the Schools went back. In June, Junior School Road Safety Officers from St Georges made signs for the path which they put up with the assistance of Lorna Henderson, Road Safety Officer from Edinburgh Council. There was some posts about it at the time on the forum and they didn't last long as it seems a cyclist removed them.
I contacted them at the time and one of the things that they were looking at was getting something more noticeable than the small "please respect other path users" signs which are dotted around. The redesign of MMW may have given some inspiration.
As I was almost run down by a cyclist at this exact location (I jumped into the verge to avoid a collision), I have some sympathy for them, particularly as this is on my daily commute and I see inconsiderate cycling here on a regular basis.