Thanks all, it's pretty clear that I had got myself into landing attempt that I could not safely rescue, although of course a more skilled pilot able to hold the speed with more precision and with fewer control movements might well have been able to make it. Lesson learned! If it's going to rat-****, bin it early, as someone upthread said, there is no point in turning a practice emergency into a real one, the lesson is learned every bit as well 150' above the ground as 15 feet!