Hi Graham
Thais is what I’ve got right now

I’m back into the front mic port, the rear port gives no level, as you said, but I dont see a line level adjustment slider on my W10 device control:

it says it’s not plugged in but it also says it’s working properly and I hear the chime when I plug into it.
So I’m trying to use the front port jacked up . I’m getting some hiss on “s” words but otherwise not too bad.
Vegas 13.453
Dell Windows 10
Intel6700 quad CPU
16 Gigs RAM
3 Gig GPU