Your export matches one of my usual one Nigel...though sometimes I'll use 24 bit just to suss out if there's a perceivable difference.
Other times I'll select the track in BIAB mixer, make sure I've centred etc, & use the track actions (?) from the right click to export one at a time.
Other times I've dragged from the DAW plug in (LOTS of problems with that) after the same preparation.
I have most faith in the right click method for some reason.
I have noted, during a recent collaboration, that the levels on the BIAB tracks were quite low...this didn't bother me but required significant boosting with the collaborator after rendering from REAPER without tweaking volume.

Cheers
rayc
"What's so funny about peace, love & understanding?" - N.Lowe