Had my first lesson with my old brass teacher last week (it's been 16 years) and she set me straight.
I was playing to the side was because my muscles are stronger on one side but it will hinder any future development if I continue down this path.
Embouchure is back to center.
I'm on a larger Bach 1 1/4C mouthpiece to develop it.
Lesson of the day: don't cut corners.