Every teacher has his character and teaching style, but that is a different discussion.
I just pointed out the difference between official music education, backed by a government education policy, including study programs, exam programs, degrees and diplomas, ...
and on the other side the more informal way of teaching.
The situation in the UK and the USA is different from other countries. Because there are so few accordion teachers with a conservatory degree in the UK and the USA, there isn't much competition between teachers for teaching positions and accordion students.
In other countries, where you have masses of young accordionists with conservatory degrees, competition for obtaining a teaching post at conservatories is much more intense. As a result, you get better teachers.
What is important is to start at primary music school level. It is important beginners have well qualified and good teachers.
In the past , end 19th century up to 1960s and even later, every, excusez-moi le mot, "clown with an accordion" could call himself an accordion teacher. In many cases, these teachers were pianists who lacked the talent to become a concert pianist or good piano teacher. So the alternative was to become a piano accordion teacher... for making some money.
The accordion makers and factories liked this idea, because they could sell a lot more accordions... Commercially this was brilliant, at education level it was a disaster.
It took a lot of guts, to break with this amateuristic system, and demand equal standards for the accordion, as with other musical instruments.
I'm aware of this unpopular opinion, but why should there be different standards for accordion teachers, than for other musical instruments teachers?
Ok, in private music education, you can do whatever you like, it's a matter of money.
Public music education, it's a matter of didactics and pedagogy. I know it's not popular to share this opinions, but ask accordion teachers in public music schools/conservatories and ask their opinions.
Believe me, it was a long time before heads of music conservatories accepted the accordion at conservatory. It took many "Segovias" of the accordion to obtain this.