These photos might help others who are in the same position.
You'll need a good selection of tools and equipment.

Cross beam bracing and triangulation to side and rear
Frame is bolted to the chassis via A,B and C 8.8 fixing bolts

I wanted the rear bodywork clear of clutter so the eyebolts were mounted on the rear bulkhead
Upper seat belt anchorage Min height was met to satisfy IVA inspection……