Yes, I finally discovered that the losses you mention make a big difference at low input voltages. I just hadn't realised how much. Given the PSU I'm using is also a little low, it's no wonder I'm having problems.
Well, I intended a learning exercise here, it's certainly educational!
Now I am re-designing it for more current, I can include the range-extender at the same time.
Hi,
Yes the inductor is tricky sometimes. It's hard to nail down the effectiveness of a random inductor until it is tried in the circuit. There are a lot of things to consider here.