Gmail's spam filter "learns" from what you do, so if you mark promos you don't want as spam, you may miss promos that you really want! Instead, you should check your Subscriptions and unsubscribe from mailing lists you don't want to be on. Here are some instructions to make sure your promos do not go to your spam folder:
1. First, check to see if you have any promos in your spam folder by doing a Gmail search for in:spam from:fatdrop.co.uk
2. If you find any promos in this search, open them and mark them as not spam.
3. Open your Gmail contacts.
4. Add email@example.com to your contacts.
That's it! You're all set up to never miss a promo.