Here's an old thread that asks a similar question. We taught applications of the BSL version back at Lam Kwoon. If you ask me about the one-legged version now, I'd play it as a knee strike, mostly because I'm generally amused by hidden knee strikes in single-leg moves. Whether or not that is the original intention of the move, I can't say, but I think I could pull it out of it with a small tweak to the dynamics of it.

For me, it's not so much about what our ancestors put into it, although unquestionably, they put in a lot of good stuff. It's more about what we can pull out of it. As long as it works, it's valid.