Thinking of you @Flatwhite31. I think it took me almost six weeks to get a BFN after my MMC and I don't know why, but I found it devasting as if all last evidence of the little baby had gone. I hope you have lots of RL support.
@suntraveller any chance it could be PGP making an appearance?
@whyhastherumgone if it is a letter you have received and you asked for the full testing to be done, I would imagine it is the combined results. My paperwork has both on and I didn't get the background risk first; it just came as one. Do speak to your midwife but remember that your risk is still minuscule and the combined test has a high false positive rate.
@scottishem I got mine at the same time that I had my scan. However, with DD1 (different hospital) it was posted to me and I was told you hear by phone within 48 hours if high risk and otherwise up to a couple of weeks by letter.