It's impossible to do anything about the penalty.. we all know that any potential 'infringement' wasn't in the box. That's not something that can be overturned though.
What we can dispute is whether it was a foul at all.
If Boro feel that the multiple angles available show that Stewart wasn't impeded enough by Fry to tumble to the ground, then I'd appeal.
My view is that contact like that, when two players are running close to each other, with arms across each other, battling for possession, happens hundreds of time each game. The reason Stewart tumbles to the floor is because of where it was on the pitch (trying to win a penalty), not because of any force from Dael.
If they were running for a loose ball in the middle of the park like that, he doesn't fall over and there's no incident.
I'd appeal it.