Basically, due to events beyond my control, my remote repo was moved - I did a lot of work on my local copy in the meantime and now I really just want to overwrite everythin
I'm not an expert in github ecosystem, but why can't you just reset your remote repository url?
git remote set-url origin /path/to/your/new/remote/repository/url
You might also need to configure your up-stream branch by looking in here.
for more on git remote..., please take a look here.
git remote...