Anything can be repaired/rebuilt given enough cash…
There are national government documents and state procedures for classification and repair of vehicles. These documents define the criteria for declaring a vehicle a write off (statutory or repairable) and the repair process and procedures one follows for registration. A adjunct to this is tne vehicle manufacturers repai processes (which would exist for a VK)…
These docs and don’t reference ADR’s as such so aren’t aren’t age specific, but the WOVR process does provide an exemption for vehicles that are 15 years or older so that makes it easier from a bureaucratic standpoint as they don’t have to be declared…
However, such docs and processes provide the scope for what is a safe repair and only a fool with grab a grinder and welder will ignore such repair documents. As is always the case, investigating best practice repair methods would yield a better and safer result while winging it may see a much worse outcome.
And we can’t forget that welding structural stuff requires real skill, not back yard podgy welds layer via multiple passes which are cleaned up with a grinder each time to make them look better… You really need to know how to weld correctly… OP may have such welding skills or he may not, only he knows..
For shits and giggles, the following SA doc specifies the process to define whether the vehicle is a write off and what level of write off.
https://www.sa.gov.au/__data/assets...s-for-the-SA-Written-Off-Vehicle-Register.pdf
There are other govco and manufacturer docs that define the repair methodology as well.