I've very little else to right now Richard, I'm one of the shielders in the Uk.
I got all my info from here Richard,
/g/nanovna-users/topic/a_guide_for_absolute/78077375?p=,,,20,0,0,0::recentpostdate%2Fsticky,,,20,2,0,78077375
There's a lot to read through but Like I say, I've lots of time on my hands right now.
The NanoVNA-App software is really up to date and a huge improvement on other software that I've used in the past.
This lets you upgrade the firmware from the program which might get you up and running.
It sounds good that you're seeing a com port so that's a start.
Kind regards, James.
It can be hugely frustrating when thing don't go to plan but it looks like you're getting there.