Really the bit people seem to be missing the mark on, is whether or not my changing the region on my account will also pull my children across with me and in turn let me redeem the code on my sons account.
From research, I think it will but just really looking for confirmation.
Some advice for you, education become less relevant as time moves on and your experience becomes your qualifications.
Get writing a CV and feel good about how good you can make yourself look on paper, and don't forget that everyone embellishes.
You sound pretty secure in your role now, so feel good about that, but rest assured you'll move on to a better job either by choice or redundancy and that's OK.