I enjoyed a brief spell as a teacher at ages 11-18, before spectacularly failing to cut it as a classroom teacher.
I do, however, take private pupils in basic piano, theory, and some elementary composition. Because my playing style is very loose and not particularly technically polished I wouldn’t consider teaching above ABRSM Grade 5, but I have taught and will teach adults above this level if they wish to broaden their stylistic efforts, particularly if they are playing in church and wish to benefit their congregations.
My diatonic theory is certainly something you’ll never find in text books, nor does it belong there. I do, however, now offer classes in Music Theory and Composition which follow more conventional lines. My playing relies on pattern and flavouring of chord progressions, a style which has been developing since my teens and continues to change as I am exposed to more and more music. It’s one area of my life where I can honestly say I learn things on a daily basis.
Please e-mail me for details and we can talk about your requirements. In the event I cannot help, I know several eminent folks who can do a much better job than me, and I could introduce you.