I wouldn't go so far as Ralf in saying that there is no progress in drama! I would say, though, that progress in drama is incredibly difficult to measure, which is why we all struggle so much with levelling, etc. In reality, I know they're made progress because my GCSE kids are now producing much more interesting work, performing better and making more insightful comments on their work. However, measuring that lesson by lesson is very hard. But let's be honest, real learning doesn't happen in handy lesson by lesson chunks which neatly fit into our objectives in any subject. For ofsted purposes, I would chose a lesson where you teach a new skill, e.g. thought-tracking, and show that by the end of the lesson that can all use it successfully. Really a bit formulaic but should do the trick.