By a coincidence, I watched the same aircraft abandon an approach to Heathrow on April 5th. It seemed to start to go around about a mile from touch down. Nothing special about that, except various "spotters" noted the wheels remained down. And they remained down throughout the entire circuit back to making a successful landing.
As I was taking photos at the time, I compared the "before & after" pictures and it seems there was a difference in the setting of the inboard flaps, almost as if they had not fully deployed when the decision to go around was taken.