How can our customer's unsubscribe from our emails?

The customer can unsubscribe on the first marketing email they receive, by clicking unsubscribe link at the bottom of one of our emails. 

Or, for Holiday Extra's emails, the customer or we can fill in the following form in for the customer via: https://www.holidayextras.com/notification-centre.html 

For Essential Travel (TIF) emails, the customer or we can fill in the following form in for the customer via: https://www.essentialtravel.co.uk/notification-centre/