Hi Max welcome to the site & Datsuns. The ute looks good. Might be that a previous owner had a hit in that corner & filled it with bog rather than fixing it properly. Hope thats all you find. As for the rear spring, you can get springs with the main spring turned upside down, called reverse eye springs. These fit above rather than below the hangers front & rear so they lower the ride height but still have full movement. You can then get rid of the lowering blocks. You just have to adjust the bump stops a little (usually cut them down a bit with a hacksaw). The ute is a taily car already without the rear springs going solid. You should be able to get the springs done through a specialist like you had the second spring done. Peddars will sometimes get them for you, as a former owner of a franchise got a lot of suspension parts made & catelogued for 1200's. It depends on who the peddars owner is & what he knows. I notice your from the Central Coast of NSW, if you can get down to Peddars at Brookvale, the owner rallys/motorkhanas a 120Y sedan. He could probably get you those springs if they still are available.