Panic over, should have looked closer.
From US VISA Site : https://travel.state.gov/content/visas/en/forms/ds-160--online-nonimmigrant-visa-application/frequently-asked-questions.html
What happens to my DS-160 if I select a U.S. Embassy or Consulate where I will be applying for my visa, but end up making an interview appointment instead at another U.S. Embassy or Consulate?
The Embassy or Consulate at which you actually apply should be able to access your form using the barcode on your DS-160 confirmation page, which you must bring to the visa interview. For example, a business traveler intends to apply for his visa at the U.S. Embassy in City X, so he selects City X as the location where he will submit his application when he completes his DS-160. He then has an urgent reason to travel to City Y on business. Because there is a U.S. Consulate in City Y, he schedules an appointment for a visa interview there, using the barcode from his completed DS-160 application for appointment scheduling. The U.S. Consulate in City Y is able to accept his DS-160 even though it lists the U.S. Embassy in City X as the location where he originally intended to submit his application.