I just uploaded the long-promised videos to YouTube. I'd delayed it because of the recordings coming out very murky-sounding; the solution turned out to be simply to reduce the laptop microphone input volume. (And I recorded these in the bathroom - the tiles give nice acoustics).
I've embedded them in the updated Bayan time (15): Angry Birds (11th April 2012) and Libertango (18th April 2011) posts, and the direct YouTube links are here: Libertango /
I'm simultaneously very pleased with the progress, and dismayed at how much better others on YouTube are: comparison reveals a lot of weaknesses in my technique. There's a long haul ahead ...