In Ivan's first biography 'Triple Crown Plus' he refers to a rider he hated but not by name. When Ivor Brown died Mauger did then quote his name as the rider he was referring to...he also kept a little black book apparently with name listed if I recall.
Apparently Carter hated Hans Nielsen for an incident that happened at the Shay...but then didn't Carter make a habit of making enemies generally. I admired, of sorts, his on track prowess but as a person disliked him. Visited his grave recently and I didn't feel any emotion other than numbness.