It just seemed a tenuous link. The Supermarine on the original is part of what the watch is about. The Bremont bus has been used most recently as part of the promotion for the Venom film which in turn is used to promote the U2/Jet and not the Supermarine. It's also just, from my perspective at least, a personal hobby for the brothers and so could just has easily have been a Porsche 911 graphic on the back (not an E-type for obvious reasons). Even though it's mentioned up thread I still couldn't tell you what type of aeroplane it is. if there's more significance than what I'm aware of then may be that could help.

Don't get me wrong, I'm not against the idea, it's just not something that particularly stands out to me either.