Best (free?) tools for learning BSL?

Hey there, I'm interested in learning BSL, but from what I've seen, the only free resources are just dictionaries, and I was hoping to find something structured similarly to how other languages are taught, such as with DuoLingo). Something with some structure, rather than just working my way through a big list.

MemRise is something along the lines of what I have in mind, although for BSL they only have finger spelling, which I learned in a few days, but nothing else.

I'd appreciate any suggestions, for paid services or otherwise.