Have you made sure to clean any gunk out of the bottom of the hole to make sure you can seat your breaker bar completely?

I've been working on Land Rovers for 35 years and, except for the PoS used on DII's, I've never come across drain/filler plugs I couldn't remove with a breaker bar, even on the Series rovers that have slotted drain plugs.
I'm at a loss why so many people have problems with them. Maybe mechanics have gotten stupider about installing them.