> Ive booked her in for another scan x
Instead of potentially stressing her with another scan (even if people says it doesn't, how do they really know), at a time when if she is pregnant, she should be living a quiet stress-free life, why not wait for the due date to come and go, and then get your vet to x-ray to confirm she's empty. I know it's frustrating not to know, especially if, given your commitments, you have a need to know, but if this was my bitch, I'd wait. By around 7 weeks in, you should see/feel puppies moving around in any case and that still gives you 2 more weeks to get your ongoing plans in place.
I never bothered with scans as I was able to clear my schedule for the length of the pregnancy going forward, and hoping for the best.