Sorry to hear of all you've been through kiwigurl.
I had repeat BTs after my D&C, mostly as I got very ill afterwards and they suspected retained products (wasn't - i picked up norovirus from hospital!). But my GP said that anyone would get repeat BTs if requested after a M/C to check levels. I am very suprised the nurse didn't offer them as part of course, let alone with questions over a new pregnancy.
Good luck with the future, hopefully if you are PG again you will have a healthy sticky bubba. I've been bleeding and spotting since week 7 and scanned every 2 weeks and all is looking good still.