I think the 8-week visit is usually just to confirm the heartbeat and check everything is progressing okay, so if you're feeling fine and your doctor didn't flag anything at 6 weeks, skipping it and going straight to 10 weeks for NIPT might work. That said, every pregnancy is different and your gynae may have scheduled it for a reason, so might be worth checking with them first why they booked you in at 8 weeks, just to be on the safe side. Most mums I know do the standard visits, but some have also managed by spacing them out a bit depending on their doc's advice.