How to show at cart/checkout a customer accounts available discounts

[PixiePawsPets]

Hello! I had a client leave a review on our website with some brilliant feedback that I would love to implement.
Is their a way to automictically show or apply at checkout a discount that they have received. For example we are using loox reviews and once a review is submitted with a photo, it prompts a automatic discount code with 15% off. Alot of clients forget or cant find the email with the code to apply on their next checkout and therefor email us with either concerns or frustrations that they are unable to apply it (We then need to go through all of the loox reviews automated discounts to find the one that applies to their account to then be able to apply it for them etc). We also offer a 10% discount for their new email subscribers who if they don't check out same day of receiving their welcoming email, they also sometimes forget and we have to confirm and apply their discount directly. We would love if their was away to automatically show if the customer (Signed in at the time of checkout) as a discount that it prompts them to be able to add their discount for example something like
"Hi (your name) you have a unused (discount code) available, would you like to apply at checkout?"

However if they don't have a discount, then to not show this as I don't want clients to get confused and think they are missing out on something that doesn't exist. 

Muchly appreciate for any help, thank you!

[GadgetsNoob]

Though not impossible. You are only allowed to do customizations beyond changing the color of the checkout of you are on Shopify Plus. This is implemented to make sure that the checkout is secured "checkout customizations" to protect both the Store and the Customer

[PixiePawsPets]

Thanks, I am not on shopify plus at the moment. Maybe would their be away to include the above idea into their account page? for example as a button option stating you have these discounts currently available?

[GadgetsNoob]

Have not tried it. But you try checkout blocks: Link 

[PixiePawsPets]

Very confusing app - Decided not to use. But thank you for your time

[tobebuilds]

What specifically did you find confusing about it?