While his baiting of the industry body Rajar continues with a court case looming, MacKenzie has tried to provoke the Radio Advertising Bureau chairman, Douglas McArthur, and the GWR executive chairman, Ralph Bernard, into fits of apoplexy.
MacKenzie's recent trade press ad campaign took a pot shot at GWR's Classic FM. TalkSPORT ran a press ad showing a hearse alongside a "note to undertakers" claiming that "78 per cent of all Classic FM listeners are over-55".
While Classic FM may well be the station of choice for coffin-dodgers, this figure should be taken with a certain quantity of salt - a shovelful in fact - given that it comes from the independent research body GfK, funded by, erm, talkSPORT.
But Bernard, unflappable as ever, refused to rise to the taunts. "We laughed," he says. "Nobody takes any notice of Kelvin's claims. If he wants to waste money that's fine but he should be spending it on proper research." Over to you, Kelvin.