Spanner nut removal

I’m trying to remove the spanner nut so I can take out the inner tub, and see if I can patch a hole in the outer tub. I read the spanner nut is supposed to have a left hand thread, so I’m trying to turn it clockwise, but it’s not budging.

Here’s a photo:

I’m ready to break it off:
What part(s) do I need to split?
Where can I get replacement(s)?

Thanks!