Peter, Since last night, I have run the config three times now with no option for WiFi config.
If you can get to the command prompt on the station in question, can you run:
lsusband
lspciat the command prompt, post it, and can someone with a working Pi3B post the same?
I'm not sure about the Pi3B architecture, but either the PCI or the USB bus will list a WiFi adaptor, if the unit has a working one. It does not need drivers for the interface to be listed.
If that doesn't help, the I would suggest comparing the outputs of:
lshwon a working Pi3B, and this one.
My gut feeling is that the WiFi adaptor will not be shown on the problem Pi3B.
Once the line for the adaptor is known, we can pipe the output of
lshw to
fgrep with a string to strip out all the other verbose stuff.
I haven't got a Pi3B here.
This only a suggestion, I'm nothing to do with PilotAware, I'm just an oik trying to suggest a quick hardware check.