I’ve got the center out and on the bench at the moment, and it is indeed twisted, it’s like a paralellogram i think. The parts themselves seem to be fine, they check out with a square. I’m leaning towards the bolt holes being misplaced perhaps its very hard to say. After striping it and reassembling it’s still out of square in exactly the same way it was before.
I’m going to reprint the XYZ’s and perhaps that will sort it out.
Or I will run and oversize drill through the bolt holes to loosen them up and give it more wiggle room so that i can tease it into the right alignment then tighten it all up.