OK - I did intermediate this morning and try as I might, during finishing I couldn't muster a solo dropback in the shala, even after multiple tries, using the wall as a prop, on my comfy thick manduka, and relying on physical then verbal cues from J. Couldn't do it alone.
So I came home, rolled out my crappy travel mat and had a go. Boom, first try! Well, the good news is at least I can still do it, thumpus bumpus landing and all. :-)