I suggest to make double sure about the measurement we are referring to. On my SM, 590 mm is the space available for fitting the entire oven set. The gimballing steel frame outer width is 570 mm and, given a 3mm steel plate thickness, the inside clearance is 570-6 equal 564 mm.
If the idea of Bryce is to place the new set on top of the existing frame, the width shouldn't be a problem. If the set is a square, the trouble is with the depth as te current ss frame is only 550mm and then, leaving some clearance for safeguarding your fingers, you run into the crash bar. This at least on my boat
Hope this helps
SM 454 Whisper, currently in Sardinia