Hi Ian, good progress on your build! Here's a picture of a 246 Chassis blueprint for reference. Interesting that your rear wheel is not centred in the wheel arch - maybe it is something Deon did to accomodate the Ford V6?? Other pictures of Deon wheel arches I've seen seem to have it pushed in the other direction.
Dino_246_Chassis_blueprint_liveauctioneers.jpg