I'm not quite there.
I'm now uncertain of the quality of my power delivery. I've tried powering the Pi from the mains (that I use to recharge my phone). Things have improved, I can see that the SD card is read and reformatted, but it doesn't get past the login prompt, it does go past that point, but I get no wifi.
I'm trying again using the more successful Anker/cable combo, but I thought I'd ask if there are any more words of advice..
Thanks for your help so far, I'm getting there. (embarrassed about the low power/brownout, but, it's always easy looking back)