This is the cross member on the chassis that is going to need to be moved so the engine can come forwards. I plan on cutting a notch out of it, rather than chopping the whole lot out, and then bracing between the new and old sections with some 2mm steel gussets.
I used some 25mm x 25mm mild steel box which is the same as the original chassis and began to measure up a new cross section.
Where the original gusset is in the top corner, it was making the new section sit proud of the rest of the chassis by about 5mm.
Some quick chopping with the hacksaw and it was sitting back flush where it should have been, job done.