Hi! I have the same coat if yours is the Heritage Kensington which based on the fit in the photo, I am sure it is. I bought mine in 2017, and it has the dark buttons which I love. In 2018, they changed to the lighter buttons.
By the way, you said you purchased the mid length, but the photo you posted is the short length which is now discontinued. It may also be why that trench is on sale as the Heritage line never goes on sale. I am sure the photo is the short length as that is how mine looks. Which by the way, I love my short! I was going to get the mid length and wear it casual with skinny jeans. When I tried on the short vs. mid length, the short was no doubt the winner.
You got a great deal! I love the short length and wish it would come back.
Here is a link to the mid length. You can see the length is much longer than your photo:
The Mid-length Kensington Heritage Trench Coat in Honey - Women | Burberry United States