Anomaly scan 18w 4d?

I just scheduled my anatomy scan for next month and was thinking I would be 19w at the time of the appt, as that’s what I told the scheduler. I just realized I’ll only be 18w 4d. I am out of town at week 19/20, so really want to keep this appt. My (UK NHS) paper work timeline says 18-20w for this scan and I’ve only don’t it at 20w before in the states. Has anyone had it at 18w and the tech was still able to see everyhing developing appropriately? I want to make sure it’s still an accurate anatomy scan at that gestational age.