Fee and Sleepy - fingers crossed all goes well for you.
They couldn't find any reason for my spotting, could see heartbeat clearly at 7+0. The lady at the EPU said that dehydration can cause spotting, so drink lots of water. I also included cranberry juice to that mix too, as urine infections can also be sneaky spotting causers. I haven't had any red spots since Monday (aside from the smudge of old blood on Tuesday).
I was also told that as you approach the times when you would normally have a period (4, 8, 12 weeks) the hormones change, and that can also trigger spots.
Try to drink lots of water and try not to worry.
If you have to wait for a scan till Monday, and have a bit of spare cash, you may get one earlier privately. I paid £120 and it was done by an experience obstretician, and the private clinics are often open in an evening. Though that is quite a lot, as others have said they can get it cheaper, perhaps it's the 'London' premium, although we are home counties.
Off to bed, sleep well lovelies (and beans) x