On more detailed inspection it seems we have our problem. The main back plate at the base was welded a good 5 degrees away from where is should be and as a result that has moved all the other plates out of alignment. If we can get them to re do the back then everything should drop into place as it was designed to.

So, assuming you can simply grind off the welds to do it again...

Remove the 9 back plates by grinding them off then swap the two bent plates over so they are on the other side and as a result bowing out not in, adjust the angle of the central plate and re-weld.