When you download your customer database into a CSV, the below information will be contained the file:
Last Booking Date
Marketing Permissions - This will have the date that the customer opted into Marketing permission. If the date is 01/05/2018, the customer will have opted in before GDPR changes on the 25th May 2018.
If you've set up extra marketing preferences at Venue group level, these will appear in Column L on-wards with the date that the customer opted in.
To see a video tutorial on how to download your Customer Database into a CSV file, please click here and watch from 01:49 - 03:10.